Dennis Bunker is Personnel Director for "the company" which we know later as Zzyzx.
Dennis takes the resignation by Tom Foss. Dennis says "Ten years of service to the company, Tom. Sorry to see you go." He makes sure Foss has supplied a forwarding address, saying "The company likes to keep in touch, especially now with Kern still MIA." Bunker reminds Tom of "how aggressively we enforce these confidentiality agreements." Before Foss leaves, Dennis asks for his security card, which Foss seems to have let slip his mind. It is like the card found with the skeleton in the woods, showing the symbol that Kyle has included in pieces on his drawings.
Some time later, Foss enters his darkened apartment to find Bunker sitting in an armchair waiting for him. He explains that when he tried to de-activate Tom's security card, it was not registered to his clearance level. It did match Kern's, who was missing from about the same time. Dennis suggests that Tom might consider that "a piece of information you might find worth something. Something you might want me to keep quiet." Told to get out, Dennis hands Tom the file folder with Kyle's records at the Juvenile Detention Center that Tom had removed, and tells Tom "Think about it. I have a feeling you don't want the company to know what you've been up to." After Dennis is gone, Tom sees that his safe had been opened.
Foss does think about it, and calls Dennis to arrange another meeting. There is a knock on his door, and he lets Dennis in saying "Let's get this over with." Expecting a large bribe for his silence, Dennis enters saying "Thought you'd come around," and continues happily into the living room saying "I under-estimated you, Tom. I didn't think the quiet guy at work...." Foss comes from behind with a swift arm across his neck.
Bunker's name is mentioned by Cyrus Reynolds as having been killed, when arguing with Tom about protecting "the boy".