You get used to big booms. I spent some time working on a military post where large caliber guns were tested regularly. The first time one went off while I was outside, I was in a crouch looking around before remembering where I was. By the time I left the contract, I would notice when a boom happened, you really can’t ignore it, but it was just a “oh, they are shooting again” reaction and not a “holy fuck, what was that?” like the first time.