The facility was in geostationary orbit above the second planet in the Taprid system. Jirenal was taken there after his arrival in the timezone. He quickly took over the Centre, draining the Pridkas' minds and using their bodies as slaves.
After the Seventh Doctor came to the Centre, Kelzen merged with Jirenal, then distracted Shanstra long enough to be killed. The damage from the loss of their mind-sister was irreparable, and they slipped into a coma. Under Pridka control again, the Centre monitored the Sensopath as they slipped into a coma and died. (PROSE: Infinite Requiem)