Lister picks up a loose chunk of roof that had been dislodged by one of his grenade explosions, and brained another climber, before looking thoughtfully at his bazookoid.

"I'll get something pointy from the next ammo run," he cheerfully tells Robert, even as he hoists the bazookoid up with the barrel to the sky. "This'll do in the meantime."

He checks to make sure that he has the firing mechanism disengaged. Don't want to blow the roof people up, after all.