Stuck...again...(Phantasy Star Universe)

On chapter 10 I think...or was it eight? It's the chapter where you have to escort Karen to some temple so she can save the world O:

I'm at the part where Lou and Ethan have to purify firey SEED.


The problem is, I'm underleveled. I can't go off and level somewhere, because it's saved just before a mission start, and I can't run away because I have to purify SEED. Any time more than three monsters pop up, I'm dead x.x


so, are there any super duper handy tricks, or do I just have to be reeeaally lucky and survive, then level up later?