Did you encounter Golem a second time? I was told I had to summon Ifrit to break down this gate next to him. Then I tried to kill Golem and nearly had it but Ifrit's timer ran out.

I learned battle mechanics in the Arena at Akademia. I tried out every single character to get a feel for their style and I also learned to roll like a fiend. No time penalty either and you get to keep your EXP and Phantoma! Give it a go!