TIFU by getting caught having sex in a public bathroom

Before anyone says it, yes I know it's wrong to have sex in public spaces. All I can say to defend myself is that, as a horny teenager with no other options, you take what you can get.

I was with my boyfriend, who I'll call Mark, in the farthest cubicle of the men's bathroom (I'm a woman), happily going at it, and I think I can hear steps outside, but I don't worry too much, since, you know, it is a public bathroom. And I think that between the elevator music and the walls and stuff they probably can't hear us.

After we're both done, we get dressed. The escape plan was as follows: Mark would look under the door to check if there was anyone else in the bathroom, and when there weren't, he would exit and text me when it was safe to leave.

So he looks, and when he deems safe, he stands up, opens the door, and leaves. I close the door after he leaves, but I thought I could see something just outside the door before I closed it. I immediately receive at least 3 texts from Mark, only containing the word "shit". What happened, apparentely, was that in the exact same moment that Mark stood up from his watching duties, the cleaning lady stepped in the bathroom, and she saw the door close, supposedly by itself, behind Mark. What I saw when the door was open was the cleaning cart thing that cleaning ladies roll around with cleaning supplies.

So I just tell Mark to overcome his shame, remain by the entrance of the bathroom, and text me when the lady leaves and I can exit. He valiantly does, even though he crosses eyes with the all knowing cleaning lady at least twice. After 20 minutes of nothing I start looking under the door as well, and I swear this woman is just rubbing the wall. There wasn't even a spot or anything. And the place she was in made it impossible for me to leave without her seeing me.

I wait.

Another 20 minutes later, she's still at the exact same place, rubbing the exact same spot of definitely clean wall. At this point, I figure she's either mentally challenged or she wants to watch the story unfold. But it's been 40 minutes at this point, and I want to leave. So I decide to wait until she moves and bolt it, and if she catcher me I'll play dumb and pretend I was taking a dump or I got the bathrooms mixed up or whatever.

So I exit the cubicle, and after exactly three steps she comes in again, sees me, and before I can put on any act, she says "I thought you were going to stay there all evening!"

I just chuckled awkwardly and left. And thirty seconds later she left the bathroom, so she probably just wanted to watch me make a fool of myself. Understandable, I guess.

TLDR: my boyfriend and I were caught having sex in a mall men's bathroom by a cleaning lady, who didn't leave until she saw me do the walk of shame.