Responses
He definitely protected him and the author wrote it like that for the cliff hanger. I mean he screamed "get down" so teach would also go down, so it wouldn't make sense. Also Guwon would brutally kill the guy if he shot teach. I think in the next chapter we might finally see the creatures that roam this world and the guy was shooting at it.

I don’t know what just happened. Was he protecting Jinwoo just now? Who was behave him why he shot?
I don’t think his intention is to kill him just now. It’s too soon to act up for him. He seems like the type to do something later down.