This is the map of old subway lines. Notice one that goes through Central Park is Q. IDK where in relation to the tents that is located, but there are DEFINITELY tunnels underneath Central Park.
>>8708054 (LB)
Related to >>8708101(LB))
I think I found something. If they did build their makeshift hospital on 5th Ave and 79th Traverse, that's where Alice is in Central Park directly across from where Godfather III was filmed.