Watch the trailer... You can hear him talking multiple times. "Here they come!" "Hang in there! We're working on getting the power on!" "There everywhere!" If you pause at 0:43, you'll see him. He's the one shooting zombies with the BAR
No, Verruckt deffenetly happens before SNN... If you listen to the CoTD Radios, you learn that Tank Dempsy was one of the marines at Verruckt, and was the only survivor. He was captured by nazis (living ones), and taken to DR where he was experimented on. The 115 made him lose his memory, and that's how Tank, "Subject N3WB" (Takeo), and "The Russian Subject" (Nikolia), were first brought together.