Hit a wall??? If you're using a tool diameter that is even bigger than the magazine can hold, you don't have much choice here on a chain style mag since it goes all around.
Is is a wall you can move or sheet metal you can remove temporarily?
The chain should alreay be set for shortest path but there's always that chance it can go the "wrong" way" around depending on who's paying attention or not. You can reset the pocket/tool numbers on the set up but there's no guarantee if someone else comes along and does something.