“Different hydrazine. Not so viciously toxic, nor so difficult to lay hands on, though it must be sought assiduously and worked with caution. But once combined with the nitrate, it is dependably stable outside the presence of fire or spark, even under the influence of magic, and powerful in very small quantities. I have used it and made it and traded it, as have many other people in the Borderlands with the knowledge and the need.” Her voice, and her eyes, which didn’t waver from mine, were steady and cool. The clinic could have air-conditioned the whole building with her. “But the gifts placed at Walt Felkin’s house were not that. No, my dear. They were gelignite. Gelignite contains nitroglycerin, which cannot be made dependably stable in the Borderlands no matter what you dope it with. Anyone who uses it here is either an unlettered fool, or a lettered one of appalling hubris. I would sooner keep a polar bear than I would a corn-kernel of gelignite.”

“If it’s that bad,” I said, “why would anybody have it here at all?”

“Because there are, without question, fools in Bordertown. Sensible people, when they find caches of unstable explosives, have them confiscated, thus reducing the communal price of folly by a few pennies.”

The dissertation on explosives was entirely Tick-Tick-like. The apparent change of subject in mid-rant was not.

“This has something to do with why you’re so angry, doesn’t it?”

She stared at me and chewed the inside of her lip. “Yes,” she said finally.

“Can you explain it?”

“To a thoughtful analyst like yourself? Probably not.” Her gaze left mine, finally, to consult the ceiling. I could have told her it was blank. She folded her hands the other way, left over right. “Astrolite requires some know-how and experience to use efficiently, and time and care to set up at the site. Whoever blew the ceiling of the apartment building had all those. What was done at Walt Felkin’s was not unlike deer hunting with a grenade. I’m sure Linn will squeeze all the relevant details out of you later, but he’s assured me that the most cursory observation of the site indicates a woefully inefficient use of materials. The blast at Felkin’s and the demolition of the apartment building might have been done by two different people. Under the circumstances, that seems so unlikely as to be laughable.”

“So that’s not what scares you.”

She shot me a glare, as if I wasn’t supposed to notice that she was scared. “What is likely is that someone with the knowledge and experience to use explosives wisely and well has, under pressure, used them sloppily and without regard for the wider consequences. Such a person, under pressure, will make no distinction between targets and bystanders.”