"I took an oath to uphold the law. Who are these people? CIA? NSA?"-The airman to Lian Xing when they meet
The Unnamed Airman is a character in Syphon Filter 2. He is an airman working at the McKenzie Airbase, where The Agency has recently been smuggling Corpses infected with the Syphon Filter Virus to avoid customs. He personally doesn't trust the government types, especially when Thomas Holman abruptly announces himself (as well as the others he's with) as FEMA.
He's later shown walking up to Carter, telling him he needs to get some fresh air so he wanted to buzzed in to go down below. After expressing his concern, he learns that two body bags were recently brought in and apparently the whole place has been locked down tight. Lian Xing, who was captured by Dillon Morgan, manages to get passed Carter into this Restricted Area and carefully sneaks her way towards a window when the airman comes up from behind with his gun readied.
She explains herself, saying he doesn't know who these guys are and the Airman holsters his weapon, confirming that fact before instructing her to come with him to the window. He allows her to escape out this way, saying that he overheard their plans to kill her. He tells her the location of the airfield and that he'll check in with the security office to cover her absence for as long as he can, while she concerns herself that he's taking a big risk here. He says that he took an oath to uphold justice, questioning then if these guys are with CIA or NSA. She says not exactly and makes her way through the window, thanking him once more.