Sherlock keeps the torch focussed on the ground at Lestrade's feet.
"The markings are just up here. We shut down the Circle and District Lines between these two stops. It wouldn't have been easy for him to get down here without getting hurt."
"No, but the lines are shut down for several hours during the night and early morning, correct? Is there footage of anyone left in the stations after the last train?" Sherlock asks, stepping over the body of a dead rat.
"We're pulling the CCTV footage now, but we don't expect to find anything. He's managed to avoid all cameras up to this point."
"Indeed." There are footprints on the ground next to where they are walking. Sherlock knows that Lestrade will have noticed them as well. "This is obviously a person of above average intelligence. He hacked into the museum's security system, are we certain he did not do the same with the CCTV?"
"They say no," Lestrade replies just as Sherlock sees the beginning of a glow ahead of them. The forensics teams have brought in extra light sources to increase visibility.
Sherlock huffs. He'll have to call Mycroft, which is annoying, but his brother will be able to find out if the system has been hacked.
They walk until a jumble of voices is coming at them through tunnel.
"How's John doing?" Lestrade asks. Sherlock has been amazed by the number of people who seem put off by asking about John. They often ignore the fact that he is ill and when they do ask it is awkward and unpleasant. Lestrade asks easily and is generally interested.
"He was not feeling well this morning, but I believe that is anxiety as he has his fifth chemo treatment tomorrow."
Sherlock turns his torch off since the light from the scene is now reaching them. Lestrade nods and looks up at Sherlock. "Let me know if there's anything I can do. I miss seeing him when we call you." It is a genuine sentiment and Sherlock appreciates it. He knows that John will as well and makes a note to mention it to him when he gets home.
Sherlock pulls his phone out and is not surprised that there is no service. John is having pre-chemo blood tests and had promised Sherlock that he'd call when he got home. Sherlock knows that John is more than capable of making it to the doctor's office and back home, but Sherlock's general over-protectiveness has only increased during this ordeal. He works desperately to suppress it because John doesn't appreciate it.
He frowns as he puts his phone back in his pocket. He's fine, he tells himself and he makes himself believe it just before he starts examining the coded message on the wall.
Cold. So, so cold. His body is aching as his muscles seize, desperately trying to stay warm. He's in Afghanistan, on patrol, at night. He never expected Afghanistan to be so cold.
Or so loud.
Afghanistan at night is rarely loud, especially on night patrol. He opens his eyes. It isn't night time. It is daytime. It's so bright it hurts. His eyes drift close again.
"Doctor Watson." He doesn't recognise the voice. "Doctor Watson, open your eyes for me again. Stay with me, please."
He opens his eyes and sees a pretty woman with long red hair. She smiles at him and he smiles back. She's really very pretty. When was she stationed here? Why hasn't he met her before? Will she have dinner with him?
No, no they can't.
"Sherlock," he mumbles, his teeth chattering.
"We're trying to get him, Doctor Watson, but his phone is either off or out of service. We're calling him though."
"Cold," he says. "So cold." Something moves by his legs and it's warm for a moment and then suddenly colder. It's cold everywhere, all over his body. And he's wet. Cold and wet.
It must be snowing, like when he'd make snow angels with Harry.
It's dark again and so loud. He wonders if the noise is friendly or foe. Nobody said anything to him about American patrols. One of the voices is American. It sounds familiar.
"Hugo," he says, but his tongue doesn't feel like it is working.
"Right here, John," he says in that booming Hugo voice. "I need you to open your eyes, buddy. I need you to stay awake. We're trying to find Sherlock."
"I'm cold," he says again. Hugo will get him a blanket.
"Not surprised," Hugo replies. "You're fever spiked while they were taking your blood. We've got you covered in ice."
"Oh," he says. That makes sense. Where is he? He tries to reach his arms up, he wants to cross them and warm up. They won't move.
Why didn't he insist on sleeping in the truck? He's a captain and a doctor. He deserves the truck not the sand. Why had he picked up a guard shift? He's a doctor in a war. There are better things he could be doing.
It's so loud.
And his arm hurts. "We're putting in an IV, John. We need to get you on some medication. We have to get this fever down. Can you help me out, John? Can you keep your eyes open for me?"
"I'm tired," he says, surprised to realise it. He doesn't remember getting tired, he doesn't remember doing anything.
"I know you're tired, John, but I need you to keep your eyes open for me."
"Sure."
The room is so bright. The light hurts. There's Hugo, standing next to him. There's an IV and he's hanging another small bag next to it. John tries to focus on the words, tries to figure out what they are, but he can't read it. It's blurry.
"Amoxicillin," Hugo says, "We don't know what you have yet."
John tries to nod but can't move his head. It's cold by his neck and it hurts. It's cold everywhere.
"Where's Sherlock?" John asks. Beautiful, beautiful Sherlock. He wants to look at Sherlock. He misses him.
"Don't know," Hugo says. "We were hoping you could tell us, we can't get him."
John closes his eyes. It's Afghanistan again. It's the desert and it's loud. Is it friendlies? He doesn't want to get shot again. It hurt. Shot. He went home when he was shot. He opens his eyes and Hugo isn't there anymore. He can hear him.
"He has a case," John whispers. He's so tired. He just wants to sleep. He's cold and he's tired.
"It's ringing," he hears somebody's voice.
He never knew the desert could be so cold. He hates Afghanistan and he wants to go home.
"Mr. Holmes, it's Hugo."
Sherlock stops moving, his feet suddenly nailed to the concrete. Something is wrong with John, he knows by Hugo's formality. His hard tone. The fact that it wasn't John on the phone.
"What happened?" Lestrade stops walking in front of him and turns around.
"John spiked a fever while waiting to give blood. It's high, Mr. Holmes, very high. I'm with him at University College A&E. Dr. Ryder is on the way here." Hugo pauses and Sherlock's stomach rises in his throat. Sherlock wants Hugo to stop speaking. He needs to shut up. John is fine, Sherlock just left him at home two hours ago.
"I'm going to cut to the chase, Mr. Holmes. You need to get here, now. It, well, it isn't good right now."
Sherlock just stands there. He doesn't know. He is nothing.
"Sherlock." It's Hugo again, but it isn't. Lestrade is pulling on the phone. Sherlock lets it go.
"What hospital?" Lestrade says and he and Hugo converse. They need to go. They need to go now.
John, he has to get to John.