That sounds like the most typical work party story ever. People make romantic advances, often can't judge the reaction correctly and it's awkward afterwards when everybody sobers up.
It's much more awkward the next day after drunk sex in a deserted office though.
Fifteen minutes later, the office manager joins in, interrupting, and starts hitting on me in a pretty blunt way. I enjoy female attention but that was a bit much. I tactfully hint that I'm not interested but she doesn't picks it up so I leave early, a bit salty.
The next morning I arrive to work and see an elevator about to close so I rush to catch it. She was inside! The following three minutes were the most awkward elevator ride in my life. I felt bad for her to be honest, maybe I shouldn't, but it must be so embarrassing when you sober up.