It's nothing. He almost says it, almost lets go, let 'whatever will happen, happen'. It's a pattern he's fallen into harder and harder over the years of his station, becoming just a spectator to the lives unfolding around him. Hold nothing.

"...I suppose it's proof of what I was saying before," Koumyou says, instead, still staring at their hands. "If you weren't what I called you, then you wouldn't see anything you weren't already expecting to see."

Not everyone on the train has been blind to his true nature, per se, but Koumyou hasn't detected even a hint of the usual off this guy. When Koumyou plays, he plays along. When Koumyou is sad, he moves closer. When Koumyou surprises him, it doesn't seem to be because Devero's decided on a pattern that the priest must fit into.

And back home, he might count those who see him like that on one hand. Or less, if the people must be alive. Sanzo-sama this and Sanzo-sama that. Sanzo must teach, Sanzo must not eat meat, Sanzo must be wise and good and save us all from ourselves.

His son sees him. Jikaku sees him. Maybe Ukoku, but... maybe not, come to think of it. Not if he'd really thought that Koumyou would stand by and watch his son die in his place.