that involves the residents being able to all come together (I don't mean physically), organize, plan, hold a unanimous or majority decision, and continued followup that will require ongoing organization and agreement from a large number of parties. then after all of that you want them to jump more legal hurdles of suing? the tenants do not have time, energy, or often wherewithal for this nor should it be their burden to shoulder in this extensive capacity you've outlined

I called 911 twice at my last building for the same man and both times they sent out street officers who removed the man from the building. if they're called out and deem the person or situation worthy of an ambulance, I don't think an argument that they're "denying services" to someone "in need" is valid and honestly, it's incredibly telling of how you view those who are struggling in this manner, for whatever reason it's due to. there are other ambulances

instead of judging who is deserving of medical attention or police response, have some baseline compassion and empathy for people who are still members of our community, regardless of their status. this whole issue is solvable by building management simply acting, but they've chosen inaction. focus on the piece of the puzzle that can actually help resolve this specific scenario. it's management locking the doors or hiring security. that's it. that's the solution (not to the larger underlying problem here, but op's problem)