Tyra's burn monster talent does roughly 11.7% damage every .6 seconds. When Raum has his complete soul armor, that's 8k health. Tyra with burn monster does about 936 damage every .6 seconds, and that's not including weapon shots. Enough said.
When Khan tries to grab you, rewind him. When Khan ults you off the stage, use setback. You can even rewind him after he battle shouts to take away the heal. And with that, you've taken away Khan's best abilities.