His irises contract to burning pin-pricks of rage and fear. His dying scream bursts up at me, an explosion of bubbles filled with fury and desperation. He thrashes like eels making love. Furious love. Self-destructive, end of the world, break-up-sex love. I feel the tension in his neck, the ebbing of his pulse beneath my hands. As his heart stops beating I become aware of mine, pounding like artillery in my head. His eyes, finally, go dull.
I realise I’ve been holding my breath, as though from some reflexive sympathy. I exhale an explosion. It’s as if my lungs want to throw up at what I’ve just done. They’re not alone. I collapse into the water, sitting beside his floating body. They say most people drown in water less than three feet deep. As my head stops spinning, the metaphysics of it starts to swirl through my mind. Is this murder, or suicide? Is it either, if I’m still alive afterwards?
Contrary to what you may believe, the past cannot be changed, even with time travel. Oh, you can try, but all you really do is cross over into a parallel universe – one that bursts into existence the moment you step back; one where your presence in the past, and the change you made, are simply how it always was. This seems like a trivial distinction – the sort of thing that doesn’t really concern you while you’re designing flux capacitors and growing miniature black-holes in your basement. It’s only when you return to the present that you realise what it really means. You haven’t changed your reality; you’ve side-stepped into another one. One where you never needed to travel back in time. One where you’re surprised, one day, to hear your front door open and find another you walking into your perfect life. Because that’s what you have to do, if you want to keep the change for yourself; you have to walk into this other self’s life.
Disposing of a body is difficult, but it’s made easier by the fact that no-one will ever be looking for it. You’re home and showered just in time. You look up from the book you’re pretending to read as you hear the door open, and smile as she walks back into your life.