diff --git a/game.cpp b/game.cpp
index 917444b6..4657094d 100644
--- a/game.cpp
+++ b/game.cpp
@@ -2747,12 +2747,32 @@ bool nogoSlow(cell *to, cell *from) {
 cell *pd_from;
 int pd_range;
 
+void onpath(cell *c, int d) {
+  c->pathdist = d;
+  pathq.push_back(c);
+  }
+
+void onpath(cell *c, int d, int sp) {
+  c->pathdist = d;
+  pathq.push_back(c);
+  reachedfrom.push_back(sp);
+  }
+
+void clear_pathdata() {
+  for(auto c: pathq) c->pathdist = PINFD;
+  pathq.clear(); 
+  pathqm.clear();
+  reachedfrom.clear(); 
+  }
+
+int pathlock = 0;
+
 void compute_graphical_distance() {
+  if(pathlock) { printf("path error: compute_graphical_distance\n"); }
   cell *c1 = centerover.c ? centerover.c : pd_from ? pd_from : cwt.c;
   int sr = get_sightrange_ambush();
   if(pd_from == c1 && pd_range == sr) return;
-  for(auto c: pathq) c->pathdist = PINFD;
-  pathq.clear();
+  clear_pathdata();
   
   pd_from = c1;
   pd_range = sr;
@@ -2765,23 +2785,14 @@ void compute_graphical_distance() {
     if(qb == 0) forCellCM(c1, c) ;
     forCellEx(c1, c)
       if(c1->pathdist == PINFD)
-        c1->pathdist = c->pathdist + 1,
-        pathq.push_back(c1);
+        onpath(c1, c->pathdist + 1);
     }
-  }  
+  }
 
 void computePathdist(eMonster param) {
-  pd_from = NULL;
-  for(auto c: pathq) c->pathdist = PINFD;
-  pathq.clear(); 
-  pathqm.clear();
-  reachedfrom.clear(); 
   
-  for(int i=0; i<isize(targets); i++) {
-    pathq.push_back(targets[i]);
-    targets[i]->pathdist = isPlayerOn(targets[i]) ? 0 : 1;
-    reachedfrom.push_back(hrand(targets[i]->type));
-    }
+  for(cell *c: targets)
+    onpath(c, isPlayerOn(c) ? 0 : 1, hrand(c->type));
 
   int qtarg = isize(targets);
   
@@ -2818,14 +2829,33 @@ void computePathdist(eMonster param) {
             continue;
           }
 
-        c2->pathdist = d+1;
-        pathq.push_back(c2); reachedfrom.push_back(c->spn(i));
+        onpath(c2, d+1, c->spn(i));
         }
       }
     }
   }
 // pathdist end
 
+struct pathdata {
+  void checklock() { 
+    if(pd_from) pd_from = NULL, clear_pathdata();
+    if(pathlock) printf("path error\n"); 
+    pathlock++; 
+    }
+  ~pathdata() {
+    pathlock--;
+    clear_pathdata();
+    }
+  pathdata(eMonster m) { 
+    checklock();
+    computePathdist(m); 
+    }
+  pathdata(int i) { 
+    checklock();
+    }
+  };
+
+
 vector<pair<cell*, int> > butterflies;
 
 void addButterfly(cell *c) {
@@ -3770,6 +3800,8 @@ int moveval(cell *c1, cell *c2, int d, flagtype mf) {
   // actually they just run away
   if(m == moHunterChanging && c2->pathdist > c1->pathdist) return 1600;
   
+  if((mf & MF_PATHDIST) && !pathlock) printf("using MF_PATHDIST without path\n"); 
+
   if(hunt && (mf & MF_PATHDIST) && c2->pathdist < c1->pathdist && !peace::on) return 1500; // good move
   
   // prefer straight direction when wandering
@@ -4379,7 +4411,7 @@ void removeIvy(cell *c) {
 
 void moveivy() {
   if(isize(ivies) == 0) return;
-  computePathdist(moIvyRoot);
+  pathdata pd(moIvyRoot);
   for(int i=0; i<isize(ivies); i++) {
     cell *c = ivies[i];
     cell *co = c;
@@ -4461,7 +4493,7 @@ bool isTargetOrAdjacent(cell *c) {
 void groupmove2(cell *c, cell *from, int d, eMonster movtype, flagtype mf) {
   if(!c) return;
 
-  if(eq(c->aitmp, sval)) return;  
+  if(c->pathdist == 0) return;
 
   if(movtype == moKrakenH && isTargetOrAdjacent(from)) ;
 /*  else if(passable_for(movtype, from, c, P_ONPLAYER | P_CHAIN | P_MONSTER)) ;
@@ -4518,7 +4550,8 @@ void groupmove2(cell *c, cell *from, int d, eMonster movtype, flagtype mf) {
       return;
     // in the gravity lands, eagles cannot ascend in their second move
     if((mf & MF_ONLYEAGLE) && gravityLevel(c) < gravityLevel(from)) {
-      c->aitmp = sval; return;
+      onpath(c, 0);
+      return;
       }
     if((mf & MF_NOFRIEND) && isFriendly(c)) return;
     if((mf & MF_MOUNT) && !isMounted(c)) return;
@@ -4532,12 +4565,12 @@ void groupmove2(cell *c, cell *from, int d, eMonster movtype, flagtype mf) {
       if(c->mov[j] && canAttack(c, c->monst, c->mov[j], c->mov[j]->monst, af)) {
         attackMonster(c->mov[j], AF_NORMAL | AF_GETPLAYER | AF_MSG, c->monst);
         animateAttack(c, c->mov[j], LAYER_SMALL, j);
-        c->aitmp = sval;
+        onpath(c, 0);
         // XLATC eagle
         return;
         }
     
-    if(from->cpdist == 0 || from->monst) { c->aitmp = sval; return; }
+    if(from->cpdist == 0 || from->monst) { onpath(c, 0); return; }
     
     if(movtype == moDragonHead) {
       dragon::move(from, c);
@@ -4545,15 +4578,15 @@ void groupmove2(cell *c, cell *from, int d, eMonster movtype, flagtype mf) {
       }
     
     moveMonster(from, c, revhint(from, d));
-    from->aitmp = sval;
+    onpath(from, 0);
     }
-  c->aitmp = sval;
+  onpath(c, 0);
   // MAXGCELL
   if(isize(gendfs) < 1000 || c->cpdist <= 6) gendfs.push_back(c);
   }
 
 void groupmove(eMonster movtype, flagtype mf) {
-  sval++;
+  pathdata pd(0);
   gendfs.clear();
   
   if(mf & MF_MOUNT) {
@@ -4602,9 +4635,9 @@ void groupmove(eMonster movtype, flagtype mf) {
   if(movtype != moDragonHead) for(int i=0; i<isize(dcal); i++) {
     cell *c = dcal[i];
     if((mf & MF_ONLYEAGLE) && c->monst != moEagle && c->monst != moBat) return;
-    if(movegroup(c->monst) == movtype && !eq(c->aitmp, sval)) {
+    if(movegroup(c->monst) == movtype && c->pathdist != 0) {
       cell *c2 = moveNormal(c, mf);
-      if(c2) c2->aitmp = sval;
+      onpath(c2, 0);
       }
     }
   }
@@ -4665,7 +4698,7 @@ int snake_pair(cell *c) {
 void hexvisit(cell *c, cell *from, int d, bool mounted, int colorpair) {
   if(!c) return;
   if(cellUnstable(c) || cellEdgeUnstable(c)) return;
-  if(eq(c->aitmp, sval)) return;
+  if(c->pathdist == 0) return;
   
   if(cellUnstableOrChasm(c) || cellUnstableOrChasm(from)) return;
   
@@ -4690,7 +4723,7 @@ void hexvisit(cell *c, cell *from, int d, bool mounted, int colorpair) {
     moveHexSnake(from, c, d, mounted);
     }
 
-  c->aitmp = sval;
+  onpath(c, 0);
 
   // MAXGCELL
   if(isize(hexdfs) < 2000 || c->cpdist <= 6) 
@@ -4698,18 +4731,18 @@ void hexvisit(cell *c, cell *from, int d, bool mounted, int colorpair) {
   }
 
 void movehex(bool mounted, int colorpair) {
-  sval++;
+  pathdata pd();
   hexdfs.clear();
   
   if(mounted) { 
     if(dragon::target && dragon::target->monst != moHexSnake) {
       hexdfs.push_back(dragon::target); 
-      dragon::target->aitmp = sval;
+      onpath(dragon::target, 0);
       }
     }
-  else for(int i=0; i<isize(targets); i++) {
-    hexdfs.push_back(targets[i]);
-    targets[i]->aitmp = sval;
+  else for(cell *c: targets) {
+    hexdfs.push_back(c);
+    onpath(c, 0);
     }
   //hexdfs.push_back(cwt.c);
   
@@ -5202,7 +5235,7 @@ int movevalue(eMonster m, cell *c, cell *c2, flagtype flags) {
 void movegolems(flagtype flags) {
   if(items[itOrbEmpathy] && items[itOrbSlaying])
     flags |= AF_CRUSH;
-  computePathdist(moMouse);
+  pathdata pd(moMouse);
   int qg = 0;
   for(int i=0; i<isize(golems); i++) {
     cell *c = golems[i];
@@ -5367,7 +5400,7 @@ void specialMoves() {
       }
     
     if(m == moNecromancer) {
-      computePathdist(moNecromancer);
+      pathdata pd(moNecromancer);
       int gravenum = 0, zombienum = 0;
       cell *gtab[8], *ztab[8];
       for(int j=0; j<c->type; j++) if(c->mov[j]) {
@@ -5469,7 +5502,7 @@ void specialMoves() {
 
 void moveworms() {
   if(!isize(worms)) return;
-  computePathdist(moWorm);
+  pathdata pd(moWorm);
   int wrm = isize(worms);
   for(int i=0; i<wrm; i++) {
     moveWorm(worms[i]);
@@ -5732,7 +5765,7 @@ void consMove(cell *c, eMonster param) {
   }
 
 void moveNormals(eMonster param) {
-  computePathdist(param);
+  pathdata pd(param);
 
   for(int d=0; d<8; d++) movesofgood[d].clear();
 
diff --git a/monstergen.cpp b/monstergen.cpp
index f021f244..9053e047 100644
--- a/monstergen.cpp
+++ b/monstergen.cpp
@@ -304,6 +304,7 @@ eItem wanderingTreasure(cell *c) {
 
 void wandering() {
   if(!canmove) return;
+  pathdata pd(moYeti);
   int seepcount = getSeepcount();
   int ghostcount = getGhostcount();
   if(cwt.c->land == laCA) ghostcount = 0;
diff --git a/shmup.cpp b/shmup.cpp
index 5f3e5dcf..867f8f78 100644
--- a/shmup.cpp
+++ b/shmup.cpp
@@ -2937,19 +2937,12 @@ void turn(int delta) {
 
   for(int t=1; t<motypes; t++) if(exists[t]) {
   
-    pd_from = NULL;
+    pathdata pd(1);
+        
     // build the path data
     
-    int pqs = isize(pathq);
-    for(int i=0; i<pqs; i++) {
-      pathq[i]->pathdist = PINFD;
-      }
-    pathq.clear(); 
-
-    for(int i=0; i<isize(targets); i++) {
-      targets[i]->pathdist = isPlayerOn(targets[i]) ? 0 : 1;
-      pathq.push_back(targets[i]);
-      }
+    for(cell *c: targets)
+      onpath(c, isPlayerOn(c) ? 0 : 1);
 
     int qb = 0;
     for(qb=0; qb < isize(pathq); qb++) {
@@ -2961,8 +2954,7 @@ void turn(int delta) {
         // printf("i=%d cd=%d\n", i, c->mov[i]->cpdist);
         if(c2 && c2->pathdist == PINFD && gmatrix.count(c2) && 
           (passable_for(eMonster(t), c, c2, P_CHAIN | P_ONPLAYER) || c->wall == waThumperOn)) {
-          c2->pathdist = d+1;
-          pathq.push_back(c2);
+          onpath(c2, d+1);
           }
         }
       }