But when Michael makes her stand against Cornwell and the whole Federation establishment, she's been there, she's made that mistake already.

That's true. As she herself says, she acted out of fear. Yes, it wasn't selfish fear but fear for others, primarily Georgiou, but Cornwell, Sarek et all by agreeing to MirrorGeorgiou's plan aren't acting out of selfish fear, either. And by letting Michael tell Tilly in the first Mirrorverse ep that fear is what motivates Terrans, the connection is underscored as well.

re: Lorca's amount of time with the Federation, the number he gives (no matter which version) is from the day he and Michael arrive at the Charon backwards, though? The question then is how much time has passed between Context is for Kings and Vaulting Ambition. We know it was six months between the battle of the Binary stars and Michael's arrival on the Discovery, and in the next episode Voq and L'Rell mention it's been seven months since the battle, so I suppose we can roughly go with "one month between episodes".


Anyway, re: Landry, agreed that Lorca undoubtedly manipulated her and pushed her towards an "ends justify means" mentality - but the thing is, Lorca is manipulative towards everyone. And undoubtedly, he picked Tyler as the next security chief because he thought Tyler would be loyal to him personally above the Federation given their shared escape, and due to the Kingon imprisonment would be more ready to use brutal methods if needs must. BUT Tyler, leaving aside his inner Voq, still shows no sign of behaving Landry-like. (Saru, now, Saru being willing to put the Tardigrade through hell even after being told it is likely sentient and suffers in order to save the crew could be the result of his months with Lorca, but then again, it could just as well have been the result of having gone through the loss of the Shenzou and Georgiou.)

I think what prevents me from seeing Landry as tragic is that we're never given a scene where she does anything sympathetic. There's also a difference between, say, Stamets being introduced as snarling into Michael's general direction and the open contempt Landry displays towards all the prisoners with lines straight out of a prison movie. Stamets gets later scenes showing he's actually good at his chosen field, and that he has ethics (substituting himself for the Tardigrade), and that while he has an ego, he's not above actually listening to Michael's imput when it's warranted. Landry in her two episodes never shows regard for anyone but Lorca, never shows even a hint of concern for the people of her ship or anywhere else. Even a minute of showing her with, say, a holo of the Buran (if she served there, though presumably she left/was transferred before it met its fate?), looking sad, or perhaps having to arrange space funerals for all those dead bodies from their sistership and declaring she will do anything to ensure this won't happen to Discovery - anything like that would have helped making her more dimensional, but we didn't get it.