Which line provides the best evidence that Himmelstoss is unstable and hesitant to fight in All Quiet on the Western Front?

For about the first half of the novel, Corporal Himmelstoss exercises considerable control over the young recruits’s lives. A sadist, he enjoys making them suffer more than he actually tries to make them better soldiers. When their resentment boils over, they join forces and attack him in his bed. When they actually get into combat with him, however, it is a different story. He is clearly unprepared for the conditions they are all facing. During one attack, the men must jump into a dugout, then rally and run back out onto the field. Noticing that Himmelstoss is missing, Paul jumps back into the trench and finds him trying to hide. He has what Paul describes as “a small scratch,” which he is using to try to pretend he is wounded. Paul orders him to get out, but he does not move. Now he is dehumanized into dog-like behavior.

“Out!" I repeat.
He draws up his legs, crouches back against the wall, and shows his teeth like a cur.
I seize him by the arm and try to pull him up. He barks.