There it is; waste of time. John takes some pleasure in knowing he at least knows Sherlock well enough to figure that bit out. Close enough, anyway. Nothing like the fact that killing is wrong or that it's just not something you do, nothing like what most people would say. No.

It's a waste of time. And John just feels fond about it, which definitely isn't normal. Ah, well.

"See that you do."

Being "distressingly" safe almost sounds very... not tempting. Whatever exactly it means. Doesn't matter; he still doesn't think he wants it.