This is a "Wild Mass Guess" entry, where we pull out all the sanity stops on theorizing. The regular entry on this topic is elsewhere. Please see this programme note.
Streets of Fire
Streets of Fire and The Warriors take place in the same universe.
The Walter Hill verse.
Building on this, Reva Cody and Mercy aren't just played by the same actress, they're the same character; Mercy is Reva's nickname. Following the events of The Warriors she and Swan leave New York, but they eventually part ways and by the start of Streets of Fire Reva has settled down alone in The Richmond and started running a diner, escaping the fate of being trapped in her old neighborhood with several kids and a cockroach-infested apartment.