ToME: the Tales of Maj'Eyal

I expected something like 2.0's probability travel but for the life of me I can not figure out how to use this ability. I get a blue square on impassable terrain but even when I try to use it nothing happens.

Any help?

You can only move through terrain as thick as the skill level says you can.

So if it says you can move through 5 squares, it will fail on 20 square thick walls.

Interrestingly enough, it doesn't work if you don't target a blocked tile, making it's use a a combat escape rather dubious.

You have to start right next to the wall you want to pass through. It is also limited to the eight cardinal directions of travel.