Okay, so I rewatched Iron Lung recently (yaay digital release!!!) and it made me realise something about that last deal Simon makes with Ava (to get the blackbox data from the SM-8 in return for his freedom/rescue) that I didn't catch before.
This may just be me being dumb, so feel free to ignore me if so lol, but before Simon mentions the SM-8, Ava tells him she can't pull him up for a few reasons; the tow-line broke, they can't risk sending someone else down to get him (cus his life isn't a good enough reason to possibly lose someone else too), and he's still welded into the sub, so there's really no way to get him out anyway.
And then, after the deal is made, two of those reasons are overrided for the sake of the blackbox's importance; doesn't matter if the tow-line is broken if Simon can get to the mouth of the cave again, and if Ava goes down to fetch him.
But he's still welded in. And Ava's just coming down in another, presumably quite similar, submersible (the SM-14, which looks very much like the other SMs while in Elli's jaws lol), not some giant different ship that could, idk, put Simon and the Lung in a cargo bay or some shit until it resurfaces and they can cut him out.
Which makes me think that Ava knew this. She new it was still impossible to get Simon out; to save him. But she needed that data, and she was willing to risk her life to get it. But she needed him on board to do so. And to get him on board, she needed to say he'd FINALLY actually get his freedom.
Simon was never ever going to make it out alive, even if the final deal went perfectly.
There was just no way to get him out. Ava was just down there for the blackbox, and if she didn't get Elli-ed, she probably would've just transferred his and the SM-8's blackbox data into her blackbox, and went back up. He was destined to die down there the whole time, despite how many times he was told he wouldn't.
"Hope is as illusory as the starlight"
