They ran. They didn't know where they were going, other than away, but they ran anyway. It was what they did.
There was no TARDIS waiting to whisk them away this time. They were on their own now. There's a time bracelet round Ace's wrist that only works sometimes but they get by. Ace had asked him to come with her and he'd said yes without a second thought. He doesn't regret it, not really, he'd follow her anywhere and they're making a difference. That's what matters in the end. There's some big grand master plan out there as the Daleks and the Timelords circle each other and time attempts to eat itself but it doesn't really touch them. They went where the bracelet took them and fight Daleks wherever they find them. Every victory is both vitally important and trivial in the grand scheme of things but the alternative is giving up and that's not something either of them has ever been any good at.
At times like this though, when they're running hand in hand, with the wind in their hair and victory in their hearts there's nowhere else he'd rather be.
They looked out over the destruction of the city; below them things still flared and occasionally exploded in showers of sparks as the infrastructure of the Daleks occupation gradually disintegrated. A particularly impressive explosion forced an instinctive “wicked!” from Hex's lips without him initially noticing.
“Oh my god, what have you done to me? I'm enjoying explosions and nearly dying. This is mad.”
She looked back at him from where she was leaning on the balustrade looking out over the destruction and grinned at him proudly.
“Beautiful isn't it?”
Ace's hair had fallen loose from her usual pony tail and was blowing around in the wind. Behind her the sun was setting, all purples and reds and oranges. In a few moments she would be perfectly outlined against it and he wouldn't be able to see her expression any more, but for now he could see how peaceful and content she looked right now.
“Gorgeous,” he agreed quietly.