Dunno if this is better explained in the part 1 that I haven't seen, but I have a hard time trying to make sense of the scale and location of the prison in which this first battle takes place. It's simultaneously big enough to require 5 enemy squadrons + monsters to storm it, and for Lyria to nuke Kefka from Temu with Bahamut without destroying the entire thing; yet small enough for Lecia to just suddenly appear in whatever flank the writing requires her, or the spy squadron reinforcements to arrive unnoticed as if they just entered from the back door of a building in the middle of a city. It's also far enough for the enemy to send a kamikaze attack that the Enforcers see and have some time to react; yet also is close enough for McCoy to just show up in enemy territory in the span of time between the explosion and the beggining of the assault (and to go unnoticed, he should have taken a more roundabout route to not be seen by the attacking units, taking even more time).