"We attacked a teacher
. . . . we attacked a teacher . . .," Hermione whimpered, staring at the lifeless Snape with frightened eyes.  "Oh, we're going to be in so much trouble –"

For some reason I always pictured Hermione doing a sort of mincing tiptoe potty-dance when she said this, though I couldn't figure out a way of effectively communicating this in the still drawing so she's just sort of lamely standing there.

Peter Pettigrew goes looking for mercy in all the wrong places (not that there's a right place; not in that crowd, anyway).  
 ...Ron was staring at Pettigrew with the utmost revulsion.  "I let you sleep in my bed!" he said.  (pg. 373, US)

Harry's response is a bit more blunt.  "Get off me!" (pg. 375)

   

 "Of course," said Black, and the ghost of a grin flitted across his gaunt face.  He, too, began rolling up his sleeves.  "Shall we kill him together?"
   "Yes, I think so," said Lupin grimly.
(pg 373, US)

This is illustrating Lupin's line, which I always heard in my head sounding like Derek Jacobi playing Cadfael.  I just included the previous paragraph for some context. 

Old friends reunited and reconciled, working together to achieve a common goal – really, this belongs on a Christmas card or something.

This picture should come before the previous two, chronologically, but I thought it more fitting to end the page with it.