Fire alarms (understandably) stress my kids out so much. Lukasz grabbed the first shirt he could find, which was a) inside out, and b) way too small, but somehow got it on anyway. Poor guy was shaking so much he needed help getting his arms through his raincoat sleeves. :( Lily was similar, but had better luck with her clothes. When we got back upstairs, she asked for a cup of tea to calm down.
(Side note - this is when it is really nice to live in an apartment building where so many of the neighbours are familiar to us. We know the strata council president, and found him in the foyer, and he took the time to explain to the kids what exactly had set the alarm off [repairs in the sprinkler room] and reassured them that it was totally safe to go upstairs again.)