While fighting the Ghoul Boss on my Hard mode playthrough Aerith was grabbed by the boss while in it's incorporeal stance while being simultaneously hit by 2x Firaga. (I believe I staggered him).
Because of the height of the mob when Aerith was grabbed it pushed her through the ceiling of the arena and the final cutscene in the warehouse began to play.
After the cutscene all 3 characters were in combat still but located at the exit to the facility. I have been unable to find a way out of this scenario as of yet, but I thought I'd drop this info here for y'all. Initially the game freaked out and crashed, but it does create an auto-save, so you can reload the point and it seemed stable after that.
There's potential skip if necessary (doubt it), but also as a warning to make a safety save before the Ghoul boss until someone finds a way out of this.