"Someone's accessing the main control units on Sub-Level 3." He called up the data. "See? He's using
a code from last month, and the computer flagged it. "It has to be Fett. He's trying to shut us down." Xarran contemplated his response. "Send three squads down to... no, wait. Seal off that room immediately. We'll flood it with Chemtrox gas and that will be the last of our little bounty hunter." Tyrix's voice lowered. "But what if it's not him...? And even if it is he could have some technicians―Xarran pushed the Commander out of the way. His fingers flew over the console and a smile slowly dawned on his face. Fett was shutting down systems and there was no time for moral debate. The race was on again and this time Xarran would win. 

Fett whirled around as the heavy blast doors sealed and locked. He was effectively trapped. So, they finally discovered his trick and now knew where he was. It certainly took them long enough. Of course it was too late. Fett was about to cut the power. He was so absorbed in his work that he almost missed it... luckily, his sound sensors picked up the recessed vents clicking open and the slow, steady hiss of gas being pumped into the room. A quick scan revealed the substance to be Chemtrox-an extremely lethal agent. Fett had heard it
delivered a particularly painful death. He didn't intend to find out firsthand if the rumors were true. Fett activated his armor's enviro filter seal. It protected him from harmful or deadly atmosphere and there was a two-hour supply of air. As the Chemtrox gas swirled around him Fett prepared to shut down the main computer. -Pgs.41-42