Mass shooters probably don't go in with the delusion they're going to survive. It's kind of like a "you're coming with me" situation like the post above says.
Bank robbers, they're usually a special kind of stupid. A crime like that takes a lot of planning, but a lot of times they aren't very planned out. There are factors to consider like the money being marked, or having serial numbers, and external cameras from every store in the area. But nah, most are like "I'MMA GET DAT MONEY." Robbing a bank is a pretty poor idea, probably from a lack of better ones.