The Niqols were truly terrible with negative emotions. Despite Liiza's cold and aloof character, she couldn't help but break down in Khan's embrace, seeking as much support as possible to deal with that inconsolable anguish.
The past weeks also played a part in that teary outburst. Liiza had always known about the inevitable separation. Still, she had held back until the last second, building up feelings that she couldn't suppress anymore now that she was alone with the person she trusted the most in the universe.
Khan was no stranger to that sad mood. After all, he had adopted the Niqols' way of experiencing feelings long ago, and the mental connection with Liiza worsened his already terrible heartache.
Nevertheless, Khan's selflessness became a valuable asset. Liiza wanted to break down, so he had to step it up, suppressing his pain to act as a pillar his wife could rely upon.