I still have no idea how I survived this on this particular run... its the only part of the fight I tended to have trouble with but I guess the game let me off this time.
I wonder why/how though.
If you have a decent computer you can upscale the resolutions and emulate the current final mix (also that's all 2.5 FM is going to be anywho. Pre-rendered cutscenes are the only thing that won't upscale.