
In case anyone is interested in the novel
https://www.novelupdates.com/series/to-help-you-understand/ only a few chapters are translated
https://page.kakao.com/home/%EB%8B%B9%EC%8B%A0%EC%9D%98-%EC%9D%B4%ED%95%B4%EB%A5%BC-%EB%8F%95%EA%B8%B0-%EC%9C%84%ED%95%98%EC%97%AC/53706168
This is the raws for the novel. Kakao allows a free chapter per day, you can try MTLing if you don't understand Korean.
Novelupdates also has a spoiler thread on the novel. Spoilers tend to ruin manhwa (not novels) for me, so I haven't looked at it. You can search it up easily using "당신의 이해를 돕기 위하여 novelupdates."
He most likely has trauma from either his sister or mother drowning. That's why he reacted the way he did with Hani floating on her back like that.
And for people who are telling Hani to do her job, she has been and is doing her job. Hani is being a bit unprofessional with the way she threatened to kill her employer who she is supposed to be protecting. I will say she was provoked, see my comment about Ashan choking her out below.
But she still protected (or tried to protect) him when he got sniped. Unfortunately, it ended up looking like she tried to save Asuka instead (who seems like a sneaky-ass yandere bastard, no offense).
Ashan has issues and takes it out on practically everyone around him. A contract goes two ways, Hani has to fulfill what her contract entails, but the employer also has to respect his employees. Things like breaking her phone, forcing her to swim by childishly threatening to damage his own health is not proper behaviour, and not to mention manhandling the back of her neck and forcing her underwater. The only reason he's getting away with this is because of his character settings - violent, ill-tempered, overpowered prince male lead.