Desperation
The rain of feathers didn't stop, but Khan could avoid everything that tried to fly toward him. Carrying Liiza inevitably slowed him down but only slightly. He remained fast enough to dodge the monster's threatening ability.
Liiza and Khan didn't say anything to each other, and she didn't try to jump down either. The crisis had already made her confirm that her weight barely affected his speed, and it was clear that she couldn't deal with the feathers on her own, especially after losing an arm.
Khan couldn't feel the pain radiated by his right arm. He didn't even think about his broken knife. Only the sensations caused by the falling feathers and the exit of the valley existed in his mind.