How the hell she just brought her senior to a love hotel out of nowhere? That part clearly doesn't add up, and the author didn't bother to try.
The obvious implication seems to be she accosted Sempai shortly after witnessing her leave the gay bar (or whatever) and promptly used the opportunity to drag her into the hotel. Note that Sempai still appears to be wearing the same outfit as in the "busted!" flashback frame...
This was strange to me too because the dialogue suggests that the senpai had no idea why she was suddently being accosted on the bed and that's when she finds out she was spotted, so why did she go along with her kouhai to the hotel and the room she got in the first place?
That aside, not a fan of this one. Senpai is clearly not interested if her own internal thoughts are to be believed. At least it was mercifully short.