In her defense, it had been a good plan when she'd done it. After all, despite what the Doctor had said, the TARDIS wouldn't be involved in events after the time connection thing was severed, right? The 51st century would no longer be connected to the 18th, and therefore he could jump back right after then and pick her up, right? It made sense when she'd jumped on the horse.
Then again, what really made sense was that she couldn't let him be the one trapped here. He had the TARDIS, between the three of them, he was the only one with a chance of finding a way back--and Emergency Programme or not, he was the only one who'd make sure at least Mickey would get back to her Mum. That program had never been tested on automatic, for obvious reasons. It might not work. More importantly, it meant he'd have his ship, and even if he couldn't get her, he'd still have a life. He'd never make it here on the slow path. And...she can handle herself in alien situations, she knows how to adapt and not get killed. She couldn't let Mickey be the one to be trapped here--it was his first trip out!
Her plan was still a better one when it included the TARDIS re-materializing in the ballroom a few seconds after she saved the day. Or minutes. Or hours.
It's been almost six hours, all told. The Doctor hasn't come.
Still, it could be worse. She could be scheduled for a beheading or banishment or something for bursting through a mirror in the middle of a royal ball...event, dressed like a madman. Man probably being the operative word.
But no, she hasn't even been escorted out of the palace yet, so that's good. That makes it easier for the Doctor to find her once he manages to land in the proper century. (He's probably in 1658 right now...relatively).
Or maybe he's out there, in this time, landed on the wrong one of those stars through the window, caught up in an adventure as soon as he stepped out of the TARDIS.
Could he be looking up from one of those stars right now, looking for the one that's Earth?
...That's a bit dramatic, isn't it? No, he's probably just sitting an hour in the future, ruffling his hair apologetically.