Von Ratched, arrogant bastard though he was, recognized the sincerity in Jace's tone. Unlike most people, he really wasn't making an idle threat--and he didn't seem like the type who would hesitate, either. Even Lorna had paused, however briefly, before attempting to hack out his heart--Jace, he was sure, would not. He'd killed before already, after all, intentionally and rationally. It would not do to underestimate him, but Von Ratched hadn't lived this long by ever underestimating anyone.
"I have no doubt you would, if I gave you the chance," he said, almost mildly. "I do not, however, intend to give you one." Definitely not. He didn't want to even risk getting burned again--or to experience firsthand any of Jace's other powers, fascinating though they were.