Did Joe Manganiello discus his plans ahead of time with Matt Mercer?

At the culmination of the Critical Roll campaign, in an act that has now become canon in DnD Joe Manganiello’s character Arkhan

I have seen and read various articles about this but one thing that I have not seen discussed is to what extent was Matt Mercer the DM knowledgeable of Joe’s plans, watching the stream at one point Matt says, as if to Joe directly

Which indicates he knew what Joe wanted to do if the opportunity arose.

Has Matt discussed this at all? Joe has discussed in great detail his plans and what happened after the events of the episode but hasn’t talked about the out of game planning and discussions at all.

I am interested as a DM as following on from watching this campaign several of my players have discussed the possibility of doing similar surprising things to the party and I would be interested to know how Matt handled this, either in up fron planning, or thinking about what might transpire next.