Very well done, HPM! Loved it... well, the shipper in me loved it. The JC lover in me hates you for "killing" Johnny again!
And hasn't Aeryn been through enough?
Sheesh! Now that I've gushed and ranted, here's your constructive criticism on the piece in general.
I love the structure
It's easy to understand, switching from Aeryn's to John's POVs, and easy to see when we're switching. The voices for both are clear and with a few exceptions, sound like the characters (case in point, Aeryn wouldn't use the word cause, as in short for because, only John would).
I also loved that you used Aeryn's POV since that's one that is often overlooked.
I like the tone and pace of the story, too.
I would like to see you keep the tense consistant, though. All present tense would be challenging but would sound best since the story is mostly internal, in their minds. We tend to think in the present tense, not the past. Try to rework the tense. If you can do all present tense, then WOOO HOOO for you. I still haven't managed it successfully in any of my stories.
Anyway, keep it coming. I love your ideas!