Keigo doesn't know if he should believe Tonbokiri. Even with his special powers or status or whatever "being a sword, really" counts as, he's not sure he can do much to protect a breakable human from a long fall. But he has to believe him. There's no other way he can go on.

"I'll still be here."

He makes sure his grip is extra secure and hopes even harder they make it to the top.