it's weird he escalated that fast, but the reason why he "just doesn't ask" is literally a chapter ago there was a flashback with "i won't push it right now i'll wait till your ready talk." yesung is too traumatized to open up and at least geol is trying to respect that small bit.
Their relationship so far has always been "let's get our frustrations out first and talk after" he thinks yesung will eventually open up, he can't know what is happening EXACTLY he just knows that his boss is a creep towards him but not that he's been grooming him this whole time
Gyeol is actually so annoying. He senses something is up with him, but instead of just asking, he just has to make it sexual