Yep, some of my passionflowers do that, too. But they are much deeper-rooted than mint which tends to stay close to the surface as long as there's lots of water.
I think if you sink a big enough pot, and leave the rim a couple of inches above ground (like the ones in Sandy's picture) you shouldn't have problems containing it. Maybe put some little pieces of window screening over the drainage holes to make it more difficult to escape. In addition, if you use microsprinklers and it has its own sprinkler inside the pot, plus there's no water outside around the pot it will tend to stay put.
