Blargh. I cannot stand mice. D: (Oddly enough, I've kept hamsters and rats as pets -- I love rats! -- but mice give me the heebie-jeebies. And to spot one running across the floor? Yikes!)

I'm amused that it was bold enough to not run away as you photographed it.

As someone said above, mouse poo (and pee) is not good for you. You've already seen how much they poop, but they pee EVERYWHERE, leaving a trail for them to follow. So yay on you for humanely getting rid of the thing. May no further mice darken your door.