Something similar happened to me, my friend and I had two boxes with about 5 mice split between them. She was driving and I was a passenger, with the mice in boxes at my feet. Well wouldnt you know the little buggers chewed out of the boxes, and crawled onto my toes. I freaked out and grabbed one, luckily it didnt try to escape at all, kinda funny actually just sat there on my foot while i scooped it up and put it back in the box.