To me, it does make sense that Astarion thinks our Tav is in league with the mindflayers who captured him: It is implied that he saw us walking around the nautiloid while he was still trapped in his pod. Before some of the pods were damaged, the cultists we encountered were the only ones who could roam freely, aside from the mindflayers. So I think it is quite understandable that he assumes that our Tav is also a cultist, and should know about the parasites. Unlike Gale, he does not know anything about tadpoles and ceremorphosis, so interrogating a cultist would make sense.
Of course, putting a dagger to someones throat is clearly not a nice action, but it is something my Tavs could excuse under these circumstances, when everybody must be extremely tense.
As for the attack option: I think the option to attack should be there for every companion - or for none. Personally, I would not attack any of our companions, but if players want to choose this option, it should be equal for all companions.
Last edited by Lyelle; 31/07/22 01:30 PM. Reason: Added: Attack Option