Well, you can't deny the possibility

I always have to read the full post before I realise which Harry we're talking about.

He had his cart in front of him, and also saw other people run into the wall without difficulty. Plus, what sort of person gets a coma by running into a wall?

Or possibly because his aunt and uncle were horrible to him so he runs away but gets hit by a car or bus, goes into a coma then never really recovers and lives in a fantasy world where he is "the chosen one"

Why would he go there in the first place then