Follow the map below to the Coliseum.
Head straight north and prepare for a boss fight.
Boss: Behemoth
This boss can be tough, so start by casting "Blink" and "Protect" multiple times to lessen the damage taken, then use your strongest magic. I find physical attack deals less damage than your elemental magic level 3.
Once you defeat the boss, you'll be thrown in jail.
Bestiary:
Examine the iron gate. Note that most of the rooms are empty and you will encounter monsters while inside.
Remove all equipment from Gordon as he is leaving soon.
- C-080: Antidote (Monster) - East's dead end.
Monsters: Stalagmite x2, Dual Deads x3, Dual Heads x3
East side, middle room (A) has 3 chests:
- C-081: Ether - Left chest.
- C-082: Elixir - Middle chest.
- C-083: Cottage - Right chest.
Enter the room (B) at the top-right, it leads to B1.
There is a shortcut through the wall of the first cell.
Interact with the iron gate of the third cell where Hilda resides.
Gordon leaves the party after the cutscene.
Take the exit (C) to 1F.
Exit the Coliseum.