Honestly, I can think of the perfect setup.
I have no doubt Vista is having her limits pushed as far as her parents are concerned, and the Wards are essentially her only escape. This is why she tolerates practically any level of crap the PRT, PR, or YG pull on her.
But with the upcoming shitstorm approaching thanks to Danny and (to a lesser extent) Emma, her total time spent with the Wards will likely be curtailed heavily as that shakes out.
Now, I suspect Vista would be running headlong into a pretty significant outburst, and would likely do as her power lets her. Run away, at least for a bit. A couple hours at night, wandering around and otherwise just being left alone to think and get her frustrations to cool.
...Except, who is that in the shadows? It's that Tinker! What's she doing?
And as any good Ward should(n't) do, she investigates!
And cha-ching, she discovers a way away from all the bullshit in her life! She's still pretty angry and frustrated with the whole damn mess, from her parents to the PRT...so why wouldn't she take it?
If nothing else, her new friend is making regular trips, so she can always come back if she decides not to stay...