THERE IS A MOUSE UNDER THE RUG?
it may seem gross, but the best way to get it right now is to grab a vacume! Hurry before it goes away! press down on the sides of the carpet surrounding the mouse so it can't escape and yell for someone to get you the vacume!
I doubt very much that there is a mouse under your rug. However, if there is, just lift the corner of the rug and it will run out and probably out of the premises if you have the door open. It is probably more afraid of you than you are of it. Mice are timid creatures and won't hurt you. I live on a farm in a farmhouse and have experienced many mice and grow fonder of them everyday....although I don't want to share tenancy with them.