They'd told Mrs Hudson, not wanting her to expect the worst if she came across a needle one day. Besides that, Sherlock wanted her to know what to do in case of emergencies. She took it all rather in stride, seeming almost too enthusiastic about practising on the orange with the glucagon injection.
Mycroft had known, of course, probably even before John had figured it out, in that unnerving way he tended to know things.
To be honest, Sherlock had forgotten about Lestrade.
They were called to a crime scene, nothing too excited, maybe only a five, but they both needed to get out of the flat. John was moody, still suffering the effects of having been running high for the most of the previous day and night, and wasn't in the mood to put up with Sherlock blowing things up, making a mess, or running off.
"Sherlock, would you stop acting like a child!"
"I'm not," he retorted, sounding exactly like a five year old.
"You're acting like that kid you had to interview last week. Remember her?"
Sherlock scowled at the thought. "Yes, well at least I'm not high, thank you," he'd snapped.
"Sherlock?" Lestrade asked, eyes wide with incredulity. "What are you talking about?"
Sherlock ran over that sentence in his head. It probably didn't sound the best to an outsider.
"John, this one's all you," he declared, stalking off towards the body.
"John?" Lestrade asked, raising a solitary eyebrow. "Something you want to tell me?"
John grinned, pulling his pump out of his pocket to show it to the Detective Inspector. "Diabetic. Sherlock was referring to a high blood sugar rather than a drug high. Of course, he tends to make things sound the worst possible way they could."
Lestrade crossed his arms. "How come I'm only finding out now?"
John shrugged, slipping the pump back in his pocket. "To be honest, it never really came up. It's not like we spend much time standing around talking about anything other than how annoying Sherlock is being."
Lestrade nodded. "How long has it been?"
"About a month now."
"And how has Sherlock been about the whole thing?" Lestrade asked.
"Not bad," John replied. "It's been hard for him, because now I actually do have to eat, and sometimes I feel like crap just when he's ready to run off after a suspect or something. But after I had my first serious low a couple weeks ago, he ran out and bought what seems to be the entire stock of Tesco's glucose tabs." He grinned at the thought, recalling all the strange places he'd been discovering them lately. It was almost like a game.
Lestrade nodded. "I'd like to know more. Go out for a drink some time?"
John nodded, and pointed at Sherlock.
"I think you should probably interfere," he explained, watching Sherlock gesture angrily at Anderson, snatches of the conversation drifting over, none of it pleasant.
Lestrade set his face in a grim line and stomped over, bellowing louder than all of them to quit behaving like children.
John couldn't help but grin as he headed over behind him.