While rn it’s weird, the way he acts ultimately does retroactively make me feel less bad about it.
I think because they are high ranking hunters they have a better sense of danger.
They can instinctively tell that something is off with this guy in the way he acts towards Seonwoo. He's glaring at Seonwoo and is not staying on task. He isn't acting like another regular team member on a mission. He is TOO focused on Seonwoo and they can sense it. They already give him a warning to quit it and stick to the mission and he keeps honing in on Seonwoo.
Their top priority is keeping Seonwoo safe so the second they perceive a possible threat they will act on it.
I don't know what he did but their overreacting(at this moment)man like his only talking to him(my opinion definitely going to change if I know the real reason)