Ubercommander Hans can be found at the end of the first volume of "The Diaries of Agent Silent Death" Freedom Chronicle DLC. Each of the Freedom Chronicles is themed after one of the gameplay altering contraptions found in the main Wolfenstein 2 campaign. The element here for "Agent Silent Death" is obviously stealth, the contraption theme ability is basically the "Constrictor Harness" allowing our agent to crawl really low, a feat you need to abuse to do this DLC on the harder difficulties.
"Agent Silent Death" is probably the shortest the Freedom Chronicle DLCs.
YouTuber "Kreeper V" 's guide on it is short and straight to the point but don't try to go gins blazing at any point during your play-through Ms. Death takes damage more easily on account of her having less health and "being small", the write-off for her stealth abilities.
Volume One begins at around "0:31" and ends around "3:13," keep in mind he does this on Mein Leben difficulty as to aid you in plotting a path into getting the "Ultimate Spy" achievement.