You did the mouse a favor,,, he was going to die as it had to be weak to let you grab it from under the couch...

Usually the whiff of a cat will make a mouse move on,,, natural preditor... Hunger or cold weather will make mice ignore the cat... One of the best preventer's is to not make food available IE closed cupboards tight structure "no breeches"... I had a stone house for 17 years and had 1 stray mouse that the catz played with till it died of weakness... I fed the mice in the garage with bird seed the whole 17 years... Field mice will quickly get used to you and feed right in front of you... I think glue traps are inhumane best to snap their neck with the good old fashioned mouse trap...