Holy shit, I know right? I tapped Auto and went to use the bathroom. When I got back, it had opened a Trick Chest and that fucking Dragon Mimic was hitting my team for 1700 3 x's per turn. I lost one team member, and used most of my healing items to beat it. First time I had done this stage, but when I did the first two groups - I thought this place was a joke and was ashamed I had been skipping it. I get to the end, only to find out its another Dragon Mimic and man.. I wish I could have seen my face, cause I was a humble, sad looking mofo. lol
..And AO - I have plenty of Metal Keys as well, but Im pretty broke after that last Super metal parade. I would imagine thats going to be your limiting factor, outside of the units you want to level up. Then, of course you gotta worry about your cost. Im also sure that that Light Team helped you beat the shit out of Maxwell, which took me a few tries.