The guard, Walker, or better known in his company by his Code-Name, Leo, turns towards Tom's direction, and taps on his earpiece, with his voice blocked off from his helmet... his NV Goggles still fully functioning, and allowing him a clear visage of Tom.
"Is the EVAC Chopper at the end of the tunnel yet, T? These guys are getting worried that we're actually with The Ringmaster... I got the footage needed to pin this 'Ringmaster' down, though... seems he's been catching these guys out in the wilderness, and holding 'em hostage for quite some time, now... I doubt if they even realize they've been capped by a crook from our standards... guy's looking at a helluva lot of jail time after this footage goes out to the media."
As he says this in his headpiece, he's double-sure that it's connected to his group's private channel, using an alternative Radio Source so as to keep the other guards out.
While waiting for Tom's reply, he lowers his mouthpiece, leans closer to them, and whispers, "There's a few more of my company that'll help out when we reach the sewers... don't worry, you can trust them."