Eventually, Sam learned of senator Steven Armstrong's ties with the World Marshal PMC and set out to take him down for just letting soldiers die while taking no personal risk to himself. However Armstrong and Monsoon, one of the senator's minions in the Winds of Destruction unit, had arranged for Sam to come to Denver, hoping to recruit him. Sam infiltrated World Marshal's headquarters through the sewer systems, in the process, running into the LQ-84i prototype. It said it had been ordered to kill him, but Sam replied it should make its own choices. Blade Wolf thought about that for a moment, but responded that it couldn't disobey direct orders or its memory would be wiped, before engaging Sam. He managed to defeat it, saying that Blade Wolf hadn't done badly, but he'd won because he chose to fight. Sam entered World Marshal headquarters, where he continued to fight his way through the cyborgs. He finally reached a hangar like area where Monsoon showed up, who mentioned his taking on an entire drug cartel, but said it would've been pointless. Sam just said he'd only been out for revenge, which he'd gotten and Monsoon said they should see what he had now.
He dropped a red phosphorous grenade down to generate a large cloud of smoke, disappearing as a Metal Gear RAY came out to fight Sam. He managed to take it down, only to be called by Armstrong, who said he'd done well, but he needed to come to the top floor to finish things. Sam managed to fight his way up to the rooftop, where he faced Armstrong himself, who thanked him for coming. He asked the senator what his game was and he replied it was Sam's final interview.
Armstrong absorbed the nanomachines from various vehicles around the building, powering up, and the two engaged each other. Sam managed to apparently defeat Armstrong, who asked him to join his cause, so as to end war as a business. Sam admitted that perhaps he'd misjudged the senator and Armstrong asked him to lend them a hand. Sam asked why didn't he just take his and attacked the senator again, finally cutting his hand off. However, Armstrong used the pointed, metallic stump to impale Sam's right arm, badly damaging it. The senator again asked Sam to join him and he agreed. Afterwards, his right arm was replaced with a cybernetic.
