There's a fairly thin corridor, running thru it is considered open terrain, no cover. So you place your model on one end with partial cover, get shot, fail guts, Can you move your model past the open terrain to the other side?
So long as you don't move closer to your attacker and you end with better cover than you started, yes.
The important thing is that it has to be "better" according to the rules, not just plausibly better. So if you're on one end, and two inches of movement gets you to total cover (relative to your attacker) on the other side through open ground, that's okay. But if you're in partial cover, and what you reach past the open terrain is just partial cover again (even if it covers more but not enough to qualify as total cover) that's not good enough. So that's going to have to be a pretty narrow corridor, or fortunate placement of the attacker.
