Agent Mills's POV
Watching a building eat itself is not something they covered in FBI training.
Standing behind the mobile command center, coffee gone cold in my hands hours ago, I stare at what used to be a research facility and now looks like God took a giant hammer to a house of cards. The chemical explosion from the sub-levels sent shockwaves through the entire structure, and now concrete chunks the size of cars keep falling into the hole where the building's center used to be.
"Ma'am." Torres appears at my elbow, his face grim. "We lost Derek's signal right after the explosion. That was eight minutes ago."
"What was his last transmission?" I ask, though my stomach already knows the answer won't be good.
"He was reporting they'd found an emergency shaft, that they were climbing to
