Light's eyes widened in confusion. He had suggested a way down without putting the ship in danger, and yet Zarev had flipped out. Despite this, and the ship getting hit by AA fire, he was right behind him after he hit the roof, landing more cleanly than Zarev had.
Light watched as Zarev cut down a pair of soldiers, then ran up behind him, putting a foot into the back of his knee, and putting the Sith's lightsaber close to his throat.
"No more killing. There is a chance we can save them if we take out whoever is causing this. One more, and I will cut you down, understood?"
Killing is not something you should do lightly in any case, let alone against friendlies. What is wrong with him?