The station had built harvesting machinery on the edge of the rift which "woke" a massive firaxan shark, believed to be the Progneitor. This firaxan had seemingly called all of the firaxans in the area and drove the Selkath in the facility insane. These insane Selkath killed nearly the entire research team save a few who were lucky enough to survive.
Revan went down to the rift station in search of the Star Map and was able to calm the firaxan by destroying the machinery, therefore rendering the station useless. Another option Revan had was to poison the shark, which would have also cleared the path to the Star Map.