Nah, by this point the Hunter Organization had already cleared the place, they'd have found him at this point. As far as he knows, Suho wants his abilities hidden, and they didn't find him in the dungeon, so the best option is to cover for him
Hmmm maybe. I feel like I wouldn't assume Suho was that much stronger than an E-rank, 3 trolls are impressive, but not sufficient to survive by himself imo. While the 7 people were protected- I'm not sure I would've made the connection. And with the complete destruction of the dungeon, I'd be very worried for him- all the more so if he suddenly isn't there.
To be honest, I'd try to call him ASAP to make sure that he isn't bleeding to death somewhere (maybe even in a hidden place in the dungeon itself unable to get help). Assuming the call can't reach someone in whatever dimension he's at, I'd then proceed to tell the high ranking guy the truth.
But idk, it's not that kind of story.