diff --git a/source/games/sw/src/sprite.cpp b/source/games/sw/src/sprite.cpp
index d8916e82b..84b2b5498 100644
--- a/source/games/sw/src/sprite.cpp
+++ b/source/games/sw/src/sprite.cpp
@@ -1634,7 +1634,7 @@ void SpriteSetupPost(void)
     SWStatIterator it(STAT_FLOOR_PAN);
     while (auto iActor = it.Next())
     {
-        SWSectIterator it2(iActor->s().sectnum);
+        SWSectIterator it2(iActor->s().sector());
         while (auto jActor = it.Next())
         {
             ds = &jActor->s();
@@ -4938,7 +4938,7 @@ int move_actor(DSWActor* actor, int xchange, int ychange, int zchange)
 
 int DoStayOnFloor(DSWActor* actor)
 {
-    actor->s().z = sector[actor->s().sectnum].floorz;
+    actor->s().z = actor->s().sector()->floorz;
     return 0;
 }
 
diff --git a/source/games/sw/src/wallmove.cpp b/source/games/sw/src/wallmove.cpp
index 8a6b9f536..4187b3039 100644
--- a/source/games/sw/src/wallmove.cpp
+++ b/source/games/sw/src/wallmove.cpp
@@ -85,7 +85,6 @@ int DoWallMove(DSWActor* actor)
     int dist,nx,ny;
     short shade1,shade2,ang,picnum1,picnum2;
     WALLp wallp;
-    short prev_wall;
     bool found = false;
     short dang;
     bool SOsprite = false;
@@ -134,11 +133,11 @@ int DoWallMove(DSWActor* actor)
                 wallp->picnum = picnum1;
 
             // find the previous wall
-            prev_wall = PrevWall(wallnum(wallp));
+            auto prev_wall = PrevWall(wallp);
             if (shade2)
-                wall[prev_wall].shade = int8_t(shade2);
+                prev_wall->shade = int8_t(shade2);
             if (picnum2)
-                wall[prev_wall].picnum = picnum2;
+                prev_wall->picnum = picnum2;
         }
     }
 
diff --git a/source/games/sw/src/weapon.cpp b/source/games/sw/src/weapon.cpp
index 23014b1f3..5e8c4370e 100644
--- a/source/games/sw/src/weapon.cpp
+++ b/source/games/sw/src/weapon.cpp
@@ -5293,7 +5293,7 @@ int ActorStdMissile(DSWActor* actor, DSWActor* weapActor)
     if (goal != nullptr)
     {
         // attempt to see if it was killed
-        ASSERT(goal->s().sectnum >= 0);
+        ASSERT(goal->s().insector());
         if (goal->hasU())
 	        RESET(goal->u()->Flags, SPR_TARGETED);
     }
@@ -7279,20 +7279,13 @@ int DoFlamesDamageTest(DSWActor* actor)
     return 0;
 }
 
-short PrevWall(short wall_num)
+walltype* PrevWall(walltype* wall_num)
 {
-    short start_wall,prev_wall;
-
-    start_wall = wall_num;
-
-    do
+    for(auto&wal : wallsofsector(wall_num->sectorp()))
     {
-        prev_wall = wall_num;
-        wall_num = wall[wall_num].point2;
+        if (wal.point2Wall() == wall_num) return &wal;
     }
-    while (wall_num != start_wall);
-
-    return prev_wall;
+    return wall_num; // should never happen unless the sector is malformed.
 }
 
 
diff --git a/source/games/sw/src/weapon.h b/source/games/sw/src/weapon.h
index e1e83a34f..7f5e28fd5 100644
--- a/source/games/sw/src/weapon.h
+++ b/source/games/sw/src/weapon.h
@@ -248,7 +248,7 @@ void SpawnGoroFireballExp(DSWActor* Weapon);
 bool MissileHitMatch(DSWActor* weapActor, int WeaponNum, DSWActor* hitActor);
 int DoItemFly(DSWActor*);
 int SpawnVehicleSmoke(DSWActor* actor);
-short PrevWall(short wall_num);
+walltype* PrevWall(walltype* wall_num);
 int DoDamage(DSWActor*, DSWActor*);
 
 END_SW_NS