This is proving rather difficult, it seems.
As luck would have it, I didn't actually save outside the Tower of Magic before I went in last time, so I had to find my way back there from Doma. As if things weren't going badly enough, I ran into Doomgaze, one of those creatures that got unleashed before, along with Phunbaba and the Eight Dragons. Doomgaze can only be fought on the Airship, so there's no need to worry about him while on the ground. Better yet, although this is a battle that will have several parts to it, the party will eventually win, as Doomgaze doesn't recover any health after he escapes.
As for the second attempt on the tower, I took the best magic users I've got for the second attempt and still died twice more. This time, it was not because the game glitched out on me, but because some of the high-level magical monsters near the top used spells that hurt both parties and wiped out mine both times.
I'm going to have to level grind a bit, so that everybody I'm going to use for this has sufficient strength and the proper spells to do this. It might take a while, but that's where I am at present. At least I did have enough sense to stock up on the proper items beforehand.
I'll be getting to this soon. See you then, everyone!