@kronix Yep, beta MC all the way. "I love her, that's why I'm just going to root her on without telling her how I feel..." I really want to see Kazuya just keep cheering her on while she's getting plowed by some alpha chad.
Also if she lost her keys, why doesn't she 1) go find her keys or 2) call her landlord to get a spare key.
I agree with
@ZeonII though. She's going to go into his apartment, then we'll FINALLY see the return of the girlfriend as she just shows up at his place -- and remember, he made a deal with her that he was only going to see Chizuru for dates and nothing was going on between them.
And yes, because our MC is the idiot of all idiots, he's going to freak out "What do I do!" and then try to hide chizuru, then the girlfriend is going to come in, she's going to try to seduce the MC, then Chizuru is going to be discovered, it's going to look like the MC was lying, blah blah blah.
Maybe we should write our own manga, pretty obvious we can be just as cliche and predictable as this trash.