Getting in serious problem now. Osamu and Chika are still too normal. A competent B-ranker needs both strategy and combat skill. Chika still relies too much on her pure strength, it is true that she hasn't got a single shot on anyone yet. I wonder why they don't use Chika's large trion reserve to form an unbreakable shield? And Chika can switch to that "lower damage but faster speed" sniper rifle. She can take the role of both gunner and sniper. With her power that small thing should still be able to penetrate houses and stuff. The faster shooting speed can help cover for her low accuracy.

About Osamu tho, I think the only thing he can do is find out a way to kill even with his low reserve. So far his role was just "the annoying weak guy who keeps pinning and distracting you". It would help more for him to have a strong but low cost kill move, like setting up slow buckshots as traps.