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What to do in the round coliseum style room
After you defeat 4 enemies in a round room, have Trico touch the button on the wall to open the rusty cells. Grab the cart from the far left cell and pull it to the center of the room where the light is shining. Stand on it and command Trico with R1. You'll be catapulted high up. Grab the grate and climb to the top.