Author's Note: The first section takes place after Peter and Olivia's conversation when they're at the van in 5x03. The second happens at the end of 5x05. Title comes from a song off Keane's newest album (for some reason, their music often makes me think of Fringe).
Disclaimer: The characters and their universe do not belong to me.
There are some things you can't undo. He knows that firsthand, in so many ways. And he has quite the list of things he would love to go back and change, things he would do differently if given the chance. Not explain away the differences in her, for one. Or, better yet, not run away from this universe in the first place. Choose to believe her that she didn't just have his Olivia's memories but was his Olivia, and not leave her standing in the rain. Play board games that afternoon rather than going to the park. And the one that's really weighing on him at this moment: stay with her no matter what the cost.
It really shouldn't have been that hard a decision to make.
After all, he had always done anything for her before. You'd think that if he could give up his universe for her (and he's done that multiple times, even destroyed it once for her, though that didn't work out so well), he'd have been able to give up one person so he wouldn't lose her.
Probably, if it had been anyone else, the choice would have been simple, maybe even easy, but then it wasn't just anyone, it was his daughter. And that was the problem. That was the reason he made one of the worst decisions of his life, the latest of a long series of things he's really not proud of.
He thought he'd been able to justify it to himself - she was strong, she didn't need him, not like his daughter did. And it was only supposed to be for just a little while, just until he found Etta, then he could come back to her, as soon as he could bring his daughter home with him. He'd told himself that she would be fine, she was out saving the world again, doing what she was best at, and she'd be okay until he could come home to her.
Now, he sees so clearly how wrong he was.
How could he have missed how much she was hurting, how much she was doubting herself? He knows why, realizes he didn't see her pain because he was too absorbed in his own, too focused on saving his daughter to see what was happening with his wife.
Turns out that he's not that much different than his father after all.
She'd said that to him, when he told her he wasn't coming to New York, accused him of letting the world burn because of his single-minded obsession. At the time, he'd thought she was furious at him for telling her the world could go to hell as long as he found Etta, but now he knows she was furious at herself, busy condemning herself for not loving Etta enough, and his refusal to give up the search just served to point straight to what she couldn't do.
He should have seen it, should have known why she was going. Maybe if he had, they would still be together. If he could turn back time, he wouldn't be so blind to her pain.
But he can't undo what has been done.
All he can do is be here for her now.
There are some things you can't undo, and he knows that this latest choice will be one of those. But this time he doesn't care, because either way he is lost. If he doesn't have their tech, they will always be faster, stronger, and two steps ahead. And if he takes the tech, he will never be the same, can never go back to who he was.
The choice is easy.
Her death has to mean something. And there is only one way to defeat them - he has to level the playing field, no matter what the cost to himself. Not so long ago, he was willing to sacrifice the world to find her; now, with the memory of her crumpled, bloody form to spur him on, he sacrifices himself for vengeance.
He feels the pain as the tech embeds itself in his brain, but it is nothing compared to the pain he has been feeling since the moment he saw her slumped on the warehouse floor. And pain is good. Pain fuels his rage, feeds the fire burning inside him, builds it until it can consume them.
If he is destroyed along with them, so be it.
It won't be the first time he has chosen destruction after losing someone he loved. He thinks now of how fitting his words to Olivia as he left the lab were. "Wish me luck..." - the same words he had used on the day he stepped into the machine. Then, he had given up his existence for Olivia. Now, he forfeits his soul for Etta. Both times, the decision is simple.
But now, as he thinks of Olivia, as he looks up and sees his wedding ring hanging on the mirror, he feels a twinge of doubt, questions the choice he's made. He has chosen to go where she cannot follow him, has left her alone again when he knows she needs him, is worried for him, is scared of what could happen to them.
The doubt is only momentary.
As things stand, this is a war that cannot be won, and Olivia (and Walter, and Astrid) will be casualties in that conflict. This is the only way he can save them. And he cannot bear to see his wife die, especially not after losing his daughter - not when he can do something to prevent it. He would rather her be hurt and lonely than dead.
And the thought of what they have done to this world, what they would do it, to his family, if given the opportunity, sparks the rage again.
He is done being an ant.
This time, it will be a fair fight. He gets the feeling they don't like those.
This time, they will pay for what they have done, for everything they have taken from him.
He can't undo what he has just done.
But this time, he doesn't want to.