In the book, it is mentioned :
Blasts in a Confined Space
When a grenade detonates in a confined space, such as a hallway or room, the gamemaster must first determine whether any barriers (usually walls) stood firm against the explosion. Consult the Destroying Barriers rules (p. 197). If the walls or doors hold up, the blast is channeled. Otherwise, determine blast effects normally. If the walls hold, the shock wave reflects off of them, continuing back in the direction from which it came. If this rebounding shock wave maintains enough Damage Value to reach a character, that character is subject to the appropriate blast effect. If the character is struck a second time by the shock wave (once as it headed out and again as it rebounded), the Damage Value of the blast is equal to the combined Damage Value of the two waves.
Does that mean anytime a grenade explodes, you're better off being far from a wall since it will most likely double the blast on you?
Or is it only used when there is more than 2 wall implied? or is it only used when the 2 surfaces are opposite?