diff --git a/apps/openmw/mwmechanics/aipackage.cpp b/apps/openmw/mwmechanics/aipackage.cpp
index 5ccd2c8d8..c2e8385b8 100644
--- a/apps/openmw/mwmechanics/aipackage.cpp
+++ b/apps/openmw/mwmechanics/aipackage.cpp
@@ -16,7 +16,7 @@
 
 MWMechanics::AiPackage::~AiPackage() {}
 
-MWMechanics::AiPackage::AiPackage() : mLastDoorChecked(NULL), mTimer(0), mStuckTimer(0) {
+MWMechanics::AiPackage::AiPackage() : mLastDoorChecked(MWWorld::Ptr()), mTimer(0), mStuckTimer(0) {
 
 }
 
@@ -92,11 +92,11 @@ bool MWMechanics::AiPackage::pathTo(const MWWorld::Ptr& actor, ESM::Pathgrid::Po
         //if(mObstacleCheck.check(actor, duration)) {
         if(distance(start, mStuckPos.pos[0], mStuckPos.pos[1], mStuckPos.pos[2]) < 10 && distance(dest, start) > 20) { //Actually stuck, and far enough away from destination to care
             // first check if we're walking into a door
-            MWWorld::LiveCellRef<ESM::Door>* door = getNearbyDoor(actor);
-            if(door != NULL) // NOTE: checks interior cells only
+            MWWorld::Ptr door = getNearbyDoor(actor);
+            if(door != MWWorld::Ptr()) // NOTE: checks interior cells only
             {
-                if(door->mRef.mTrap.empty() && mLastDoorChecked != door) { //Open the door if untrapped
-                    door->mClass->activate(MWWorld::Ptr(door, actor.getCell()), actor).get()->execute(actor);
+                if(door.getCellRef().mTrap.empty() && mLastDoorChecked != door) { //Open the door if untrapped
+                    door.getClass().activate(door, actor).get()->execute(actor);
                     mLastDoorChecked = door;
                 }
             }
@@ -113,7 +113,7 @@ bool MWMechanics::AiPackage::pathTo(const MWWorld::Ptr& actor, ESM::Pathgrid::Po
         else { //Not stuck, so reset things
             mStuckTimer = 0;
             mStuckPos = pos;
-            mLastDoorChecked = NULL; //Resets it, in case he gets stuck behind the door again
+            mLastDoorChecked = MWWorld::Ptr(); //Resets it, in case he gets stuck behind the door again
         }
     }
     else {
diff --git a/apps/openmw/mwmechanics/aipackage.hpp b/apps/openmw/mwmechanics/aipackage.hpp
index c9c8504aa..bb62a2543 100644
--- a/apps/openmw/mwmechanics/aipackage.hpp
+++ b/apps/openmw/mwmechanics/aipackage.hpp
@@ -3,6 +3,7 @@
 
 #include "pathfinding.hpp"
 #include <components/esm/defs.hpp>
+#include "../mwbase/world.hpp"
 
 #include "obstacle.hpp"
 
@@ -63,7 +64,7 @@ namespace MWMechanics
             float mStuckTimer;
             float mTotalTime;
 
-            MWWorld::LiveCellRef<ESM::Door>* mLastDoorChecked; //Used to ensure we don't try to CONSTANTLY open a door
+            MWWorld::Ptr mLastDoorChecked; //Used to ensure we don't try to CONSTANTLY open a door
 
             ESM::Position mStuckPos;
     };
diff --git a/apps/openmw/mwmechanics/obstacle.cpp b/apps/openmw/mwmechanics/obstacle.cpp
index 7cd85685b..fc781e637 100644
--- a/apps/openmw/mwmechanics/obstacle.cpp
+++ b/apps/openmw/mwmechanics/obstacle.cpp
@@ -20,18 +20,18 @@ namespace MWMechanics
     // actor is facing the door.
     bool proximityToDoor(const MWWorld::Ptr& actor, float minSqr, bool closed)
     {
-        if(getNearbyDoor(actor, minSqr, closed)!=NULL)
+        if(getNearbyDoor(actor, minSqr, closed)!=MWWorld::Ptr())
             return true;
         else
             return false;
     }
 
-    MWWorld::LiveCellRef<ESM::Door>* getNearbyDoor(const MWWorld::Ptr& actor, float minSqr, bool closed)
+    MWWorld::Ptr getNearbyDoor(const MWWorld::Ptr& actor, float minSqr, bool closed)
     {
         MWWorld::CellStore *cell = actor.getCell();
 
         if(cell->getCell()->isExterior())
-            return NULL; // check interior cells only
+            return MWWorld::Ptr(); // check interior cells only
 
         // Check all the doors in this cell
         MWWorld::CellRefList<ESM::Door>& doors = cell->get<ESM::Door>();
@@ -54,10 +54,10 @@ namespace MWMechanics
                 if((closed && ref.mData.getLocalRotation().rot[2] == 0) ||
                    (!closed && ref.mData.getLocalRotation().rot[2] >= 1))
                 {
-                    return &ref; // found, stop searching
+                    return MWWorld::Ptr(&ref, actor.getCell()); // found, stop searching
                 }
         }
-        return NULL; // none found
+        return MWWorld::Ptr(); // none found
     }
 
     ObstacleCheck::ObstacleCheck():
diff --git a/apps/openmw/mwmechanics/obstacle.hpp b/apps/openmw/mwmechanics/obstacle.hpp
index e737ef9cf..76ab9d029 100644
--- a/apps/openmw/mwmechanics/obstacle.hpp
+++ b/apps/openmw/mwmechanics/obstacle.hpp
@@ -22,7 +22,7 @@ namespace MWMechanics
 
     /// Returns door pointer within range. No guarentee is given as too which one
     /** \return Pointer to the door, or NULL if none exists **/
-    MWWorld::LiveCellRef<ESM::Door>* getNearbyDoor(const MWWorld::Ptr& actor,
+    MWWorld::Ptr getNearbyDoor(const MWWorld::Ptr& actor,
                          float minSqr = MIN_DIST_TO_DOOR_SQUARED,
                          bool closed = true);