Marker Lab was one of the seven Multiplayer Maps in Dead Space 2. It was set in the Government Sector. The Security Team was sent in to destroy all of the Marker experiments that are being conducted while continuously battling the sheer number of the Necromoprhs. Marker Lab featured 5 objectives that needed to be completed before the timer ran out. The objectives mainly consisted of deactivating the blast shields protecting the Markers and blasting them to the point of destruction.
Due to the appearance of the Necromorphs in the Marker Labs, it could be assumed that the Security Team was sent in after Isaac Clarke allowed the Necromorphs inside the Government Sector in Chapter 13.
The map had features that resembled their story mode counterparts, but they are changed in size and shape. They still retained their original concept, however.
Despite The Security Team being exposed to the Markers, they never experienced any dementia.