office rat?

one of my few female co-workers was making a leisurely trip to the bathroom, which happens to be next to my desk. she opened the door, gasped, and lept backwards. she stood still, her mouth wide open in shock. apparently a rat had charged out of the bathroom and under my desk. i asked, "a rat or a mouse?" "a rat!" she insisted. the maintenance guy put a trap under my desk and an hour later a tiny mouse was caged inside. i'm not sure what they did with it...