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Well, they also have to go grocery shopping and luckily their old fat neighbor has this tiny electric cart/scooter thing that fat or frail people use at Wal Mart, so they reprogram it with their superpowers to also fly and go faster so they take the cart from the hallway and get the hell out of there. One of them has to sit in the metal basket though but that's fine.

i dunno maybe they blast a hole through the roof?

anyways a popular author Charlie Higson wrote a book about adults becoming zombies and a bunch of kids made a base in a supermarket. it says in the back of the book that he went to a supermarket and asked them questions about where they could hide and stuff and they were delighteed to help so maybe you could do that? but if you dod do that then do it when they aren't busy..