@Acolytus You've got a good head on your shoulders. This is a mistake of the mangaka/author. He isn't taking the situation that he himself has written seriously enough. And during the suspension of disbelief it appears that these male classmates are more focused on being horny than being held on gunpoint. Pretty unrealistic even for ecchi manga standards.
@trickshot121 Believe it or not, I was still giving him a benefit of a doubt up until the page where he ordered girls to strip. And I'm considering taking up for the MC as long as he starts the next chapter with an ass whooping. My reasoning?
1. I assume that MC is (probably) faster than the man can pull the trigger. Most of my reasoning is assumption. My biggest assumption is the MC's lack of attentiveness towards the enemy. There's even a panel where he looks away from the guy completely. I'd assume a "trained warrior" wouldn't take his eye off a dangerous opponent, so this man is non-dangerous.
2. The Japanese are very, very veeeeeeeeeeeeeeeeeeeeeeeeeeerrrrrrrrrrrrrrrrrrrrrrrrrrrryyyyyyyyyyyyyyyyyyyyyyyy...
...different from westerners, in that being a conforming,
unrelentingly-conscientious person trumps helping others, speaking your mind and for the most part saving people. If something is someone else's job, "you are getting in their way by trying to help" is your first Japanese thought, not "I need to help that person". I always keep this cultural difference in mind when I see manga starring protagonists who don't want to stand out, because Japanese writers tend to use that bias unconsciously.
3. My own personal bias here, the trauma starts when they are made strip. There are probably a few who are already traumatized by the guy simply bringing out a gun. That's unfortunate, but I don't think that the MC should feel completely at fault for letting it getting to that point.
3a. He is technically a war vet. If you've met and older one, they tend to look at "hardship" with a different perspective. They either have way more empathy or way less, it seriously depends on the person. I'd say that the MC is a latter type.
3b. He has spent a considerable amount of time away from this world and his classmates. As far as he's concerned, they could be random NPCs to him. We don't know how much death and suffering he's seen, he could very well be desensitized. Although this wouldn't (in my opinion) excuse letting them suffer, it may explain why he attempted to hand off responsibility to someone who is already charged with protecting this world.
4. This one explains why the "stripping" was the breaking point for me. At this point, he had already activated a skill and heard the girl's explanation as to why she wouldn't help.
It's at this moment where he could act accordingly to stop this from going too far. But apparently he's no faster than the speed of a girl stripping. Hm.
As long as the gunman doesn't touch any of the girls, he's earned a 'pass' from me, but he's lost some points from me even so.