u/Art-Quarius

This was his first time ever stepping foot into Hell. Keep in mind he was the only one who was apprehensive about going down there and getting revenge. He then gets roughed up by Loona, even when he has the upper hand, he's not really enthusiastic about the situation. It looked like he was only doing it out of a mix of fear and self defense to me. He looked pretty hesitant while aiming at Blitzo. The cherry on top is that he gets crushed by a falling Cletus, putting him in a full body cast when we see him in following episode.

I don't think Collin wanted to do any of that, but it felt like a combination of both his spineless demeanor and pressure by his "friends" to go along with them or he would face retaliation as shown near the beginning of the episode when Cletus slapped him for questioning the morality of their pitpocketing scheme.

All of this could potentially lead to him having immense guilt over his actions and maybe even developed a bit of fear around Loona if they were to cross paths again.