John just nods assent when Dean has no suspect reaction to the knife. He supposes he should have a pang of second-hand pain for his child, cutting him open like that, but it's not a real injury in his eyes. Nothing to worry over like a stab wound or a bad hangover- it's just a part of the job.

Satisfied with the standard tests, John heaves a sigh so heavy his soul threatens to slip out with it. He's weary, tired in every way a man can be. There was a part of him that almost hoped he would fail the tests and prove to be just another monster or illusion spit out by this place. His heart is too damn heavy with Dean's pain, he still wasn't sure he could take it all on.

But shit, that's what being a parent is, right? So he just stuffs the knife back into his pants and brings the kid in for a suffocating, Winchester-style hug.