That's because she was thinking about him the whole time she was taking care of Hikaru.
He called her a light-weight which means he acknowledged that she was clearly very drunk and he still when ahead an touched her, even when she called out a different name (because she doesn't like him like the other guy) she still went ahead and continued in a scene that would have clearly escalated to him raping her or at the very least assaulting her.
she's clearly too drunk to stand up properly and barely recognised him the first time around, only really saying him name because he made her focus on him but she's clearly out of it.
when fujishima shows up she's passed out but she's clearly still thinking about him.
Also, on the note of her not knowing how much she can hold in terms of alcohol she's already said to be really naive and she clearly doesn't drink a lot to begin with so her tolerance is going to be much lower than a normal person.

Lmao casually touching her when she's drunk and says he's "treating her right". Fucking asshole