okay it's time for the make or break moment of the story. Will it fall into the pit trap of most "banished from thw party stories" with OP god MC where he was never in danger, and take any reason to be invested in this story out of the equation.
Or will the party save him and avoid the bad timeline
I fully expect him to open the chest, and find some weapon that lets him unleash his Secret Power on the boss. Hopefully it shatters after he uses it, though, so there's an actual reason to not just run around being an OP blast-things-to-death mage.