An explosion.

That's what it is, even though he only really gets it when he shows up at the 16th Precinct, panicking, even though it's his day off, but it's the precinct, and it's them, and his partner and damn the fact that he's a sergeant now.

In other news, the NYPD's 16th Precinct was struck today by an explosion that sources say originated in the Manhattan Special Victims Unit squad room…

No mention of anyone who might have died. No mention of anyone who might have been injured. Nothing. Just 'struck today by an explosion'.

Simple terms, really.

Not so simple when you're a cop.

He doesn't see Fin at the scene, which scares the hell out of him because he got there as the last ambulance was leaving and hears his own voice in the back of his head.

Officers down!

Life, John thinks at this point, has a funny way of throwing the most unexpected things at you, which is why you're supposed to be prepared, but there's no real way to be prepared.

On the floor, on the walls, can't keep his footing because it's too slippery, and so he's falling…falling….

Elliot's voice breaks into his thoughts, but he can barely hear the younger man. The precinct's been evacuated, because of the explosion. There's no telling when they'll be able to go back in.

Hospital machines, beeping, lines moving up and down, keeping track of the vital signs, going flat when there's nothing left….

It's happened before, this. Not the explosion in particular, but the feeling that comes after a partner or a colleague or someone he barely even knows, but someone who serves the same way he does is hurt.

It is the same helpless feeling that he's felt more times than he cares to count, back in Baltimore, where any minute, someone could draw down on you. And it's the same here, but somehow different. The city that never sleeps versus the city that bleeds.

I'm leaving, Kay. I can't take this anymore, and I just…I need a change.

But things haven't really changed. And he still doesn't see Fin, and he doesn't see Lake, and Elliot informed him that Olivia got sent home, and he really wants to go back to his own place, too, but he can't make himself move.

One in the head, one this close to the heart, the other in the neck and leg, and there's just so much of it, and he blinks, but it's still there, and no one answers the call.

Officers down!

No one knows where Fin went. He said something about his ear and going to nail someone, but other than that, nothing. And so he waits, at the precinct, when everyone is finally let in again.

New detective coming into the squad room because they lost another, and first it's self-inflicted, then it's murder, and not even the veteran murder police can recognize his face…

Cragen comes into the squad room and tells him to go home, an order which he refuses to comply with, because the squad room is in pieces and someone has to make it back into the way it was. But Elliot has gone home to reassure his family, Lake is still in the hospital, Olivia went home, and he still doesn't know where Fin is.

You ever pull a stunt like that, Tutuola, and I'm gonna kill you myself, you hear me?

Anger, fear, desperation, helplessness. Things he's felt before, and hoped he'd never have to feel again once he left Baltimore, but apparently he was wrong, and he's feeling it now, and he wishes it would go away.

None of us are gonna ever leave this unit in a body bag, Elliot had said once. Not one of us.

But there is no way he could know that. He wasn't paying attention when people were leaving, and he couldn't say where Fin had gone and even if he could, it wouldn't help.

Rookie detective shot in the back under his partner's eye, BPD holding a candlelight vigil outside of the hospital, murder police waiting inside, because there's no family to take their place…

In other news…

The words come suddenly, and out of nowhere, and a bitter laugh escapes him before he can stop it, because it just figures that the media would try to put some kind of spin on it to make it seem a lot less worse than it was.

The NYPD's 16th Precinct was struck today by an explosion….

Midnight comes.

He's still in the squad room. He still can't bring himself to leave, like he couldn't when the first three were shot, or when they lost Felton, or when Bayliss got shot while pursuing a suspect with Pembleton. And suddenly another thought hits him.

Abandoned intersection in the middle of Baltimore, someone else driving, cracked windshield in the shape of a spider's web, and lines…so many lines…

John closes his eyes at this point, a vain attempt to make the images go away, but it doesn't help, all it does is make things worse, and what he wants is a reassurance that he's not going to lose this partner, not going to see this one lying on a table in the medical examiner's office.

Not going to have to inform this partner's family that he's gone, because he really doubts they'd actually care.

And then there are footsteps. He wonders for a minute if it's Cragen coming back to tell him that he's got exactly five minutes to get out of the squad room before he gets a five-day rip. But it's not Cragen.

"What're you doing here, old man?" Fin's voice breaks into John's thoughts, and he opens his eyes, relieved as another scene appears in the back of his mind.

Open eyes in a hospital room, familiar smirk on a familiar face and then a familiar voice: told ya I was immortal.

Shut the hell up, Fin, you are not.

Keep saying that, you're gonna jinx me.

I am not. Now take this before the nurses see it.

"Came to see if you were ok," he replies, finally, once he finds his voice again.

There is a cut on Fin's ear. Suddenly, Elliot's words come back to him: "He said if someone was gonna bust his eardrum, he was gonna go bust their ass."

He nearly laughs at this as Fin sits on the edge of his desk, shaking his head.

"You worry too much. You're the one that got hurt last, not me."

This time, John does laugh, and so does Fin, because they're both flashing back on the same thing.

So, where exactly did you get shot?

In the ass. Want to kiss it and make it better?

You better be nice to me, old man, or I won't give you this fig milkshake I picked up.

Thanks, man.

What else are partners for?