Even if you were to do a modified set, in which the "Second level" was not a full story up - I have done this before in Noel Coward, where we needed a second level . . .
If you were to add just a few steps, the blocking, the blocking that is outlined so well in the published version of the script, would require quite a bit of change . . . so, let's say you were able to pull off the set in space confinement . . . all the business with the second level, falling down stairs, dropping sardines, people be above people and not seeing people on the different level, would all need to be restaged . . . and created.