A banality, but it would flow wherever gravity could take it. Once the cat is out the bag there's no telling by which route it will eventually escape the garden. I would assume though, that there is free passage ways from the outside surface of the drywell to the torus room, so that could be one waystation.
There's one thing I find weird about the plan of gradually filling the reactor to the very top, while finding and repairing the leaks that turn up, as you go, while the water is rising. How will it even be possible to locate the leaks? Certainly they cannot be seen from outside of the PCV, due to that pesky layer of concrete surrounding it and the fine cavity between the PCV and the concrete, which so easily will transport water elsewhere, far from the leak. How can one find the location of a leak in the PCV, from observing that it oozes somewhere downstream through cracks in the concrete shield? Do you fill the vesssel until it oozes too much then back down, lower the waterlevel find the leak repair it, then try and fill, and try and try again?
The prospects of the water filling plan, it would seem to me, will be an almost endless battle against leaks. (And no, I do not come with a better plan.)
