If Shi Nian'an were sober enough to remember the things she'd said, she'd probably want to slap herself twice for being so immodest!
In the end, Shi Nian'an bathed while Achen stood with his back to her at the door, waiting.
Shi Nian'an wouldn't allow him to close the door, so the two of them reached an odd and ambiguous understanding in that way.
You should know that Shi Nian'an was drunk as a skunk, her bathing was entirely reliant on muscle memory, and it was a complete mess; she didn't even rinse off all the soap suds properly before she wrapped herself in a towel in total disarray, covered here but not there.
The bathroom floor was slippery wet everywhere, and she, not paying attention, slipped, teetered, and tumbled over with her feet flying up in the air!
Upon hearing her screams, Achen instinctively wanted to check on her but refrained from turning around: "Are you okay?"