Bol, you won`t believe it but I just saw a white mouse running on the floor!
I am serious. Later on anotehr mouse was walking on me while I was sleeping. I woke and put it back. It turned out I had left a gap in the mice`s house.
I understand your calm since you actually breed them, so it seems. I woke up once in similar circumstances one night when sleeping over in a house, which was overrun with mice for dozens of years (of which I learned later). I freaked out, feeling one walking on my chest and seeing another one climbing up the cable of the bedside lamp. Yuck!