We were running a mini-campaign once based on the movie "Aliens." We were all playing Imperial Marines. Our ship encountered a drifting starship which, unknown to us, an Alien queen had turned into her nest, with lots of eggs inside.
My character was Stryker McGuire. I had the squad's support weapon -- a big machinegun, just like in the movie. When we got into the cargo hold and the Aliens started to attack, we were badly outnumbered. We started to fall back. I was covering our retreat through an Iris valve in the floor. Aliens kept dropping from another Iris valve in the ceiling. I kept hitting them and killing them, but couldn't stop shooting long enough to get through the opening.
Finally, I was the only one left on that deck. And I missed. An Alien got to me and hurt me pretty bad. Others were pouring through the opening in the ceiling and were advancing on me. I knew I couldn't use my machinegun any more in such close quarters, so I yelled down for the other squad members to close the valve, then I detonated a grenade. All of the other grenades I was carrying, as well as my ammo, went off as well.
Killed a lot of Aliens, though.