Larry Kaczynski

L. Kaczynski was one of the UAC scientists in Doom 3, working in the Alpha Labs. He is one of the few personnel who survived the initial invasion of Hell.

During the demonic invasion, he gets trapped in a chamber when the power went out and asks the Marine to free him. The Marine is given either the choice of freeing him or activating the chamber with Kaczynski inside. If the Marine chooses to free him, Kaczynski can access to his lab next door, containing weapons, ammo, and Michael Abrams's PDA. He then locks his lab after the Marine leaves, thinking he will be safe. His name is references to former 3rd President of Poland, Lech Kacynski.

His fate is ultimately unknown, but he presumingly perished along with the rest of Mars Base, as Resurrection of Evil states the Marine was the only known survivor of Hell's invasion.