We had a trainee taekwondo move his way into the room and he only went up to C. Why is it so weird someone else ran into the room when they went all the way up to A?

Probably because there was tension in the A rank room, and none of them clapped for any trainees that moved up. Whereas in the B-ranked room, you would see trainees like Daniel smile, clap and cheer for the ones that moved up. So in a way, it does seem awkward in that situation for Hyeongseob to react like that, when the trainees in the A rank room weren't going to react positively (at that moment)

I think most guys expected the same reaction, only this year the guys that came a threat to their position for the already A trainees. Daniel also expected more of a reaction and knocked the door to get attention. I love him, but I found that a more awkward moment honestly.

I agree with this. I guess it might have been less awkward for to see if neither of them had tried to get a reaction, when no one in the A-ranked room seemed in a good mood.