I think it’s well known Arthur lost strength with TB (evident by losing to Milton prior to Abigail shooting him) so I think they gave him TB so he didn’t obliterate Micah in the final fight. I kicked Micahs ass with TB so I think Arthur would’ve killed him without TB (and while we’re on the topic of the final fight if the objective was to kill Micah why didnt Arthur just push him off the edge of the cliff. He had multiple opportunities.