Two things I really don't get?!!

The second story, when the two chicks rob the old man -

1. If he was deaf or at least hearing impaired (as implied by the hearing aid and one of the girls), how could he have known about them messing with his denture, and subsequently shouted about them giving his teeth back when he woke up?!

2. The denture thing the girl was messing with seemed to be for the top set, yet when he is yelling, he clearly has a full set of top (if not bottom as well) teeth!!

Am i overthinking this just a bit too much ya think?!

Thanks :D