It takes her seven seconds to notice they're not alone anymore. He doesn't say anything, but his presence is intimidating enough – or would be to ordinary people, she assumes.
She's far from ordinary though, and she's not afraid to meet his eyes.
"If he dies, I cannot guarantee your safety."
His voice is like ice and steel, but there is fire in his eyes. She holds his gaze for a moment, then nods briefly.
Silence falls over the hospital room, and she glances over at Sherlock. If he dies, then Mycroft Holmes will be the last of her problems.