This is actually very common in Japan.
You see, he probably didn't really want to rob the bank as such, but wanted to be arrested due to most likey being homeless and hungry.
I often see stories of homeless men holding up convenience stores, then they just sit down outside and wait for the police to come and take them away.
Remember reading last year, how a homeless guy went to do that, and actual killed a 24year old female shop assistant, just to be arrested.