You were defending against zombies in Fallen mode.

One of the Giant Bosses were overpowering you, when suddenly a powerful shot from the Ranger's railgun took it out.

Ranger: "Heh, it almost got you there if it weren't for me." He says as he reloads his railgun, chuckling.

The Ranger then looks at you from his cliff.

Ranger: "You must be a newbie around here..."