Responses
He's a kid, a newbie. Not a veteran. He has experience but it's still not enough. Plus his biggest character point is that he CARES for people especially those he's recognized as allies. It might be cliche to you but it's perfectly in line with his character. He's not an edgelord who can turn a blind eye to an ally in danger nor does he have enough experience to hold back from reacting. Time and time again, it's been emphasized even by vlad himself that he's got a lot more to learn.
Ally gets lightly hit -> MC completely looks away from the enemy, calling out their name -> MC gets blindsided by a strong attack.
It's such a cliché at this point. He's experienced enough fights by now...he should know better...