If I recall, Musk was explaining that on the Starship booster they had recently begun to use directed venting of ullage gases for control authority to save a seperate hot or cold gas thruster system and Dodd asked if this also applies to the ship. Musk then went "now that you mention it, we should look into that". During a visit a year or so later he then confirmed they had begun doing it on the ship too and that it had occurred to him as he was explaining it to Dodd.

It's of course unlikely that the engineering team wasn't already considering this, but it's also not like Dodd was suggesting anything, he was just asking a follow-up question. The way the conversations played out was Musk remembering to ask someone about it later to check the status of the plan or drive a decision, and later recalling that conversation when Dodd came by again.