This has been a popular scam that plays on your vulnerability and your sense of insecurity when in a new environment.
Here is how it plays out;
You enter the escorts premises and you are asked for payment up front (not unheard of.)
You are told to make yourself comfortable and just before things get really heated there will be a telephone call or the intercom to the apartment will ring.
The escort will come back to tell you that her boyfriend (or husband) is on his way up and he is very suspicious.
She will rush you out of the apartment promising you another session very soon and telling you to call her later. You rush out of the apartment without your money. Panting fast with adrenalin you will make your way carefully out of the premises, whether it is down the path or a flight of stairs from her apartment.
This is a difficult scam to recover from. The escort is playing on the fact that you cannot jusdge whther it is true or not. Are you going to wait to find out if she is bluffing?
Indeed, it might actually be a fact that her boyfriend is on his way to the apartment. Of course, it may not be true. You are at a disadvantage here because whatever happens, the escort will have planned her response and thought through how to respond to any potential conflict.
We would recommend that you promptly leave the premises and write up reviews of your experience with this particular escort so that others are warned to stay clear of her. Yes, you will have lost your money but your safety should be paramount. If you are in the midst of a scam, then you need to be careful and respond quickly.