Re: Plot holes...

In responce to why he drew the drawing that he did:

Remeber that when he returned to the past in the classroom, he was the 'adult' verson of himself. He sat there for a little bit not knowing what to draw. He tried to get up, but his teacher wouldn't permit it, so what does he do? He thinks about what he will do in the future, i.e. how he will cut the two immates when he returns.

I don't know if this question was answered, but the reason why he stood there with a butcher knife was to disable to blockbuster, but was caught by his mom.