Board Thread:Questions and Answers/@comment-39492511-20190519172422/@comment-1327106-20190520055910

Even if they didn't need to save Armin, the Survey Corps would have killed Bertolt anyway. Remember what the plan was with Reiner after they got him out of the Armored Titan. Hange was going to kill him until Jean suggested they see if someone was critically injured enough that they should use the injection and have the wounded soldier eat him. Hange agreed and sent Mikasa off with a signal flare to let them know whether they should kill Reiner right away or have someone eat him.

Mikasa saw the situation with Armin and Bertolt, so she signaled that Reiner was to die. The only reason he didn't is because Zeke and Pieck arrived in time to save him.

Given what we know of Reiner's situation, there's no reason Bertolt would have been spared.

As far whether he deserved to die, that's a matter of pragmatism. From the POV of Paradis, they had to kill him because he was too dangerous to leave alive. Personal feelings couldn't enter the equation. Even if he said he was willing to change sides, how could they trust someone so dangerous? (Look what happened to the Anti-Marleyan Volunteers, and they're small fry compared to the Colossus Titan.)

I don't think Bert's an irredeemable person, but part of his tragedy is that he ended up in a position where he could never be given the chance.