Mindy’s final “guess” in Scream 6 made no sense

After the killers are all dead and the police show up, Mindy arrives and says she knows who the killer is- it’s Ethan and Bailey. This makes no sense, though. Earlier when they attempted the phone call trap and the killer ended up attacking Gale, both Ethan and Bailey were present and accounted for at the same time that the killer called Sam, so if Mindy was assuming it was exactly two killers, Ethan and Bailey would be physically impossible.