Ouch that will hurt, the unit thats is ambushed will definatly die. Im not sure on the exact rules for nids but i might say that this kind of unit ambushing and attacking in the same turn seems a bit unfair?
Maybe they become visible at the end of your turn if the roll ias succesful then any enemy wanting to shoot/assault the unit must roll to see if they can see the unit?
I dont know if ive swung it too much into the oppositons favour
Lets face it ive fought nids once in the armaggedon campaign (i had to hold that side of the board) and got wiped of the board by the genestealers regenerating back of the board!!! i kick loads aswell!!!!
conscriptboris