A big turkey has to measure a safe before he can rob it. If the safe is too big it won’t fit in his getaway van and the robbery will have been a failure. So before the turkey robs the place he needs to measure the safe.
The safe that the turkey is trying to rob ends up being uber (うば) big. Like, really uber big. So uber big that the turkey can’t even measure it with his tape measure. There’s no way he’s gonna be able to rob this place.