Sherlock frowns slightly, able to place the expression but not to decipher the sentiment behind it, and sets the moment away for examining later. The threat of being overpowered with the urge to feed should probably be a warning Sherlock takes more seriously, but even as he considers it he dismisses it as absurdly unlikely; between the two of them, the one with perfect control over their body's needs and desires was Sherlock. (Of course, between the two of them, the one most likely to let their indulgence spiral out of control was Sherlock as well, with his history of letting his vices overwhelm him -- but this does not yet occur to him.) Surely it meant nothing, that she had given in. And given in she had -- he'd noticed the almost-imperceptible flecks of blood on her as soon as he'd seen her, reading the time between each attack in the drying patterns but not really much else.

"John is keeping himself away. Ran off after I got the door open," Sherlock says, gaze flicking away from the hunger on Irene's face to look out the window deliberately. Another difference between transformations, then. Irene is at least recognizably herself, if clearly altered, whereas John... simply was no longer there. A wild animal fleeing a cage. "I won't need to go looking for him until the moon sets, if I'm not mistaken."

Though he suspects his friend will simply have to drag himself home, if what Sherlock believes Irene's intentions to be are true.