In general, damage is not needed, when a player is stating an intent of their action. That intent comes true when the player is successful. As long as their is a success, the players goal is achieved.

Multiple successes
These are used by the GM as a guideline ot the effectiveness and/or breadth of the success. If the pc tosses a grenade at an enemy soldier and rolls one success, the soldier could be unconscious, bleeding, incapacitated, but not necessarily dead. 5 successes and the poor soldier was so surprised that he caught the grenade and is currently spread across the landscape.

Player Characters have it a bit tougher .