"Sherlock? Out. He had to dash after we'd finished with our homicidal robot. I'll ask him about it later, but when he gets worked up it's better to let him go. Otherwise, he looks at you like you're wasting his time." John didn't sound angry - it was just Holmes's way. You either realized this and accepted it, or you didn't get on with him at all.
"Of course. The dime tour, I'm afraid - there's really not much flat to see. I can tell you stories. 'And here are the stairs that the murderous cabbie stood upon when he'd come to abduct Sherlock.'" John gestured grandly at the hallway for emphasis. The stairs! ...still not interesting. "I'd still like to bandage you up to keep the wound clean and to protect the area, but the bandages are in the medicine cabinet." So, really, a tour could be mixed in. As he'd said, there wasn't a whole lot of flat.
The question caught John by surprise. He blinked a few times, then laughed - an abrupt, startled laugh. "What? No." It must've been a pop culture reference to that other, Victorian Watson, because John couldn't imagine where else she'd have gotten the phrase. "I'm not sure if he's ever said 'elementary,' but I don't recall it. He calls me 'John,' and I'm not sure if he's ever called anyone 'dear.'"