The interrogator was an NKVD agent who interrogated and tortured Tanya, trying to make her reveal Einstein's location. Von Esling sent the Commander with a spy to rescue her and secure plans about a strange weapon, what was known to be the Iron Curtain.
He was about to execute Tanya, but a spy entered the room and distracted the Interrogator. Although the spy is fatally shot, Tanya takes advantage of the momentary distraction, knocking and pinning the interrogator to the floor with the chair Tanya was tied to. The dying spy tosses her a pistol, and the interrogator is killed, ironically, by his own captive.