Ken doesn't really feel much of anything, thanks to Chikusa's anesthetic. He's also not particularly bothered by Chikusa's cutting his legs open, even though he's conscious and bleeding and if he lifts his head he can watch.

They've been through worse. When it comes to most things, they've always been through worse.

Still, it's kind of weird to watch, not to mention boring. So he watches Chikusa instead...and when he sees those tears, he moves on instinct.

Chikusa hasn't cried since Mukuro saved them from Estraneo. Even when the Vindice caught Mukuro again, and Chikusa was as upset as Ken's ever seen him, his eyes had stayed dry. But Ken remembers him crying from when they were little. Chikusa would be dead silent, and then suddenly he'd be a shaking, crying mess with no warning. It had always scared and upset Ken, the way crying just exploded out of Chikusa for no reason - delayed reaction wasn't a thing Ken could understand very well even now, much less when he was a child - but he'd discovered that Chikusa calmed down easier whenever Ken curled up with him. Chikusa would cling to him and slowly wind down.

This...isn't like that at all. Never mind that it's been so long since Ken can remember Chikusa crying; he's never seen him cry like this, silently, like he doesn't even know the tears are there. Somehow that's even more unsettling, but Ken's response is the same as it always is whenever he senses Chikusa needs comfort - he reaches out. The fact that Chikusa is slicing into his legs, that Chikusa's got blades centimeters from veins that would kill Ken in minutes if they got cut...it doesn't occur to Ken to worry about them.

Chikusa is crying.

"Kakipi, why're you crying...?" He's never had to ask that before.