Any idea who provides Emergency Medical Services for Manhattan, or NY in general?

Docwagon does, interestingly enough per Rotten Apple they don't maintain many clinics and instead have a deal with Shiawase medical. But if you see an ambulence it's more then likely a DW asset.

Thanks for the reply. I will have to reread Rotten Apple. I could not remember that being int here anywhere.

It's actually in the section on Shiawase so it's understandable you missed it, search was my friend.

Yeah I read back through and found it. It is an easy to miss reference.