This is the "textbook definition" of tanking, hell even no-selling.
Pri-Pri-Prisoner leaps over the heroes and then turns around to talk to them, only to get punched in the face by the Monster. While he was distracted and off-guard, he took the punch and did not budge and only reacted to it after the fact. He was obviously unaffected by the Monster's punch.
"And you can see that that monster was able to harm him, causing his nose to bleed with its punch."
Chip damage ≠ he harmed him. The nosebleed is also only visible for a single panel. In the pages following, his nose is no longer bleeding, so this is a moot counter, considering the other piece of evidence pointed out above.