Once the Genestealers had been drawn off, the last two squads were able to move into position in the target room. The toxin had been tested on captured Genestealers, and had proved effective, but it needed to be administered in a highly concentrated form to overcome the creatures' amazing constitution.
Because of the large amounts of toxin involved, it would take several minutes to carry out the contamination. The tanks were connected to the ducting, and the contamination process was begun. Immediately the toxic gas was released into the cryogenic ventilation ducts the Genestealers sensed and reacted to the danger. All their active forces began moving towards the duct room...
Never had five minutes seemed so long. Commander Bellisario stared at the glowing green digits on the display - 1:03... 1:04... 1:05... 1:06... If only Sergeant Darius and his men could hold the room until the toxic gas was fully dispersed. All the Stealers in stasis would be killed in one fell swoop. 3:33... 3:34... 3:35... The screen showed the view down the corridor leading away from the duct room. Sergeant Medici and his squad were holding a junction round the corner. The distant sound of bolter fire reached a crescendo, there was a terrible scream, then silence. The picture jumped suddenly as the Space Marine raised his storm bolter. 3:39... 3:40... Shadows flitted into the end of the corridor. Instantly, the Space Marine fired his storm bolter, raking the advancing Genestealers with fire and thunder.
The Space Marines must defend the duct room until all of the toxins have been released into the cryogenic atmosphere circulation system. If they keep the Genestealers from destroying the fragile ducting until the toxins have been released, all of the hibernating Genestealers will be destroyed as they awaken. Then all that will be left is the mopping-up of the several thousand already active Genestealers.
Squad Darius and Squad Medici must defend the toxin canister in the duct room for 16 turns, while the toxins disperse into the cryogenic chambers.
Because the ducting is fragile, and the toxins highly volatile, flamers may not be used to fire into or out of the duct room or its entry corridor. If a flamer is fired in this area, the mission is failed.
Note that flamer ammunition is becoming scarce, and the flamer marines have no reloads.
Space Marines may begin the mission placed anywhere on the map, in any facing.
The Space Marines move first.
Two blips have already arrived. Two more will arrive each turn.