The Slave Play website says 2 hours. You also have to get out of the theater and onto the street, then at least a 10 minute walk (with all the other playgoers leaving shows around the same time) and make it to your seat in the other house. And remember, they have to screen you for the vaccine pass and security and ticket taker...you won't make it.
And I agree with the above-if you go to Slave Play, you need to stay to the end. If you leave early, you'll annoy everyone else at a critical moment in the play, and you will miss a fairly crucial scene. Better to skip it, or Phantom (which will run forever, and you could see another time).