[@duskshine749]React to what happened in the first post (whatever you think Arthur would have reacted), then with the conclusion of the banquet, feel free to just have him doing whatever. Crassus could have retired to his chambers and Arthur is free to tend to other duties. If he wants to try and save Leo, he could tell the others about what happened and they all could go investigate.

Since Bram works in the kitchen, I know he has a high chance to see Gilles and the other overseer using the secret passage in the cellar. So, if he secretly sees them use the passage, then he could tell the group how they accessed it.