Delta Labs - Level 2b: Union Aerospace Research Division is the seventeenth level of Doom 3. This level marks the first appearance of the Arch-Vile as well as the Hell Knight - albeit the latter being a partial specimen only. This level also introduces Dr. Elizabeth McNeil to the game's storyline. While she does not make an appearance in this game (she makes her first in-game appearance in Doom 3: Resurrection of Evil), her PDA can be found in her office. There is also a Martian Buddy cabinet in this level containing a BFG9000. It's the second time you can get the BFG9000.