I thought I was onto something after I managed to clip back into Saul's at the end, just found the cutout facing the wall in a corner though. I think I might've found everything I can.
Couple of thoughts after this latest playthrough:
1) It feels a bit weird that the money counter still goes into negative if you ask for a dollar off the macaroni. When using the vending machine, sure, but there's no reason for it to go into that imaginary number in this scenario.
2) The old man's sprite changing after the coin falls out of his pocket, seems like it should only happen after he's done talking, for it to line up with the sound effect.