As always, the signs were easy to read as soon as they were articulated - it was a satisfying feeling to see it all click into place, whether or not he himself had been the one to make the discovery. Greg wasn't one to worry over credit or pride. It was just as thrilling to get the answers from someone else, especially when, as with Sherlock and Mycroft, he could trust them to be right.

This time, of course, the thrill was cut off almost immediately by the plummeting feeling of something being decidedly wrong. "What do you mean," he asked, wetting his lips a little nervously, holding out hope for the moment that it wasn't quite what it sounded like. "They must have gone, if we -"

And that's when he heard the shouting. Then - a gunshot, unmistakable, and the clatter of his people taking cover, the frantic mix of radio and live voices. He was out the door into the hall before he knew it, that sick feeling taking a back seat for the moment to the crisis - to just getting a damn grip on things. "Stay there," he barked in the general direction of Mycroft and the one forensic technician looking like he might rather high-tail it out to the car, before taking off up the hallway toward the action. Just perfect.