He reached inside his dark wool jacket, took out a small black rectangular device about the size of a deck of cards, and slid it silently across the wood to my side.

“This is an encrypted tactical pager tied directly to our local duty station,” Keller said, his voice pitched so low it didn’t carry past the edge of the table.

“Walk me through how the alert works,” I said, picking up the heavy casing and feeling its smooth matte plastic.

“Pressing the rubber red toggle on the side starts a two-minute countdown alert at our tactical command center,” Keller said.

“A digital readout on the front will show the seconds remaining.”