Yes soap will get rid of Urushiol and some mechanical action is required, HOWEVER the last thing you want to do is weaken the skin and break it down with too vigorous a scrubbing. That will just facilitate penetration of the oil into the skin, and make you more vulnerable until your skin has repaired.

I get exposure to poison ivy on a regular basis but I know there's a 2h grace period in which I do all the yardwork around that stuff then jump in the shower. A normal shower takes care of it all.