Adrian isn't a good mc giving the new update. He's just there to be a civilian and not a fighter. Plus I doubt this is a romance vn.
Sorry if my opinion sounds cruel
As a first contact to that kind of situation I don't see his reaction as detrimental to the story.
He never had contact with this violent part of this world and shock is a pretty reasonable reaction to witnessing the coldblooded killing necessary to survive in that situation. Not speaking of the moral implications of killing the lions that seem to be more on the side of oppressed them that of the oppressor, trying to do best to go by in a society that only tolerates them, from what we could see so far of the party at least.
He may not have done much in this instance but it was his first mission, he more likely than not will be forced to be more active in future confrontations, aside from thinking on what he wants to do given everything he went through.