There's a little blonde mouse pushing a marble down the hallway. It's South. The mouse is South, and the marble is a bomb, and she freezes when she notices someone is there. Then, upon realizing who it is, she abandons her marble, runs tiny mouse-head first into the wall in an attempt to escape, recovers and disappears into a vent.

Then reappears a moment later to grab the marble and pull it in with her.