Cleansing of the Sin of Damnation - Pitfall: While the remaining Blood Angels fought a desperate battle against the neverending hordes of attacking Genestealers, the toxin attack proved to be a success, and all but a few hundred Genestealers had been eradicated. The surviving Space Marine squads swept the Genestealer lair for the remaining aliens and fanned out into nearby sectors to hunt down those that had escaped before the gas was released. Sergeant Lorenzo had reappeared after fighting his way back alone from the Wrath of Baal. He reported encountering a different kind of Genestealer, larger and faster than the others.Between the psychic sense of Brother Calistarius and a deep probe scan from the orbiting Strike Cruisers, the Blood Angels were able to locate two more creatures like the one that had attacked Lorenzo. Raphael ordered Lorenzo and Calistarius to take tissue samples from these aliens for future analysis, and then destroy them before they awoke. Sergeant Lorenzo pulled together an ad hoc squad from the most battle-ready survivors of the fighting. The squad was issued with portable power field generators to aid them in their mission. These could be used to close off doors and passages for a short space of time, ensuring that their prey would not escape. What Lorenzo did not know at the time was that the creature he had followed through the underbelly of the Hulk was now stalking him.Lorenzo was successful in destroying two dormant Broodlords, as the Blood Angels had dubbed the Genestealer leaders. During the encounter, Brother Zael sacrificed himself to save the Sergeant and the active Broodlord was driven off, believed dead. Isolated from the main force, the survivors of the mission were now at the heart of a rapidly converging circle of Genestealers intent upon destroying those that had slain their leaders. There was no chance of relief squads from the main Blood Angels force reaching Lorenzo and his comrades in time. Following the readings on their sensorium, the Space Marines fought their way towards the exit.Their objective was a service shaft that led out onto the surface of the Space Hulk from where they could be extracted by gunship. The tissue samples carried by Lorenzo were an important source of information about the Genestealers and needed to be returned at all costs. A few dozen metres from their escape, the Space Marines came across a collapsed deck. Under increasing attacks from the Genestealers, they had to negotiate their way across the wreckage and reach the external duct. To make matters more difficult, the Broodlord Lorenzo thought destroyed was anything but dead, and intent on tearing apart the enemies that had destroyed its brethren.In the end, it was only through the sacrifice of his fellow Battle-Brothers that Brother Calistarius was able to fight his way to the Hulk's surface and signal command from an extraction by Thunderhawk gunship. He successfully obtained both the genetic sample and the ancient Chapter relic, but only at the expense of his brothers' lives. This small force of eighty 1st Company Terminators managed to eradicate a much larger force of more than 40,000 Genestealers, cleansing the Sin of Damnation and enabling its secrets to be plundered in the Imperium's name. But more importantly, they had avenged a long-standing stain to their Chapter's honour.