No i dont want to blow up anything, just wonder about story possibilities, solely for writing. Lets suppose that dozen stun grenades blows in a room, that is at least 10m long, 5m wide, 4m tall, with a large machine(generator) in the middle, the majority of the grenades not so far from the entry door. What would someone at the other end of the room, behind the machine, experience? While no shrapnels could hit him, but blast waves reflects from the walls, and stun greandes operates with blast waves. Could the sizes of the room be enough protection, or it would be similar to standing next to a detonating grenade?