USS Darkstar

Very early in the game, a security guard is injured on an away mission to a nearby planet and is taken into the sickbay. When scientists are operating on him, a Headcrab bursts from his chest cavity, mirroring a scene from Alien, forcing the scientists to activate an incinerator. The flame jet kills the Headcrab but also detonates a fuel canister, which creates a chain reaction. This causes a surge that badly damages the USS Darkstar's main computer, deactivating all the force fields and letting loose the aliens which kill most of the crew. However, Freeman manages to reach an escape pod and escape the ship, shortly before it explodes. The game ends with Freeman's pod heading towards a nearby planet, pursued by a large alien vessel. At least one other scientist also survived the destruction of the USS Darkstar. During Freeman's entering of the labs, a scientist (Named Walter) in an escape pod elevator can be seen through a window. When reaching the escape pod launch room, one of the vehicles has already been launched.