Quote 1
Returning to the barracks he had to go along a dark, uninhabited road. There we waited for him behind a pile of stones. I had a bed-cover with me. We trembled with suspense, hoping [Himmelstoss] would be alone. At last we heard his footstep, which we recognized easily, so often had we heard it in the mornings as the door flew open and he bawled: "Get up!" (3.66)
Paul and his friends spend quite a bit of time coming up with a way to take revenge on Himmelstoss. Why do you think it is so hard for them to just let him be? Why must they execute this last act of revenge?
Quote 2
"You lump, will you get out – you hound, you skunk, sneak out of it, would you?" [Himmelstoss's] eye becomes glassy, I knock his head against the wall – "You cow" – I kick him in the ribs – "You swine" – I push him toward the door and shove him out head first. (6.148)
We're not quite sure what's up with the animal imagery at this moment, but it's clear that Paul is none too pleased with Himmelstoss's plan to hide in a dugout during a bombardment rather than fight. The man who was supposed to have taught the young soldiers about bravery and about what it means to be a soldier is the greatest coward of them all.