I knew there was something at the back of my mind when I was trying to sleep last night about the 2 megatons and a Sharlin. And as usual not only has someone found it for me, they have put it better that I ever could! Much obliged ShadowScout!
Ghost Dancer - one epsiode we saw that was "Endgame" where the EF Marines were blasting their way in to get at the telepaths Sheridan had put on Clark's Omega fleet.
The Cheat - You are right about the door and the shotgun, but now imagine that same slug hitting a window or pressure pipe. The PPG would not penetrate but the slug would.