For several minutes, the man stopped breathing. In a Beaver Hills apartment, he’d flooded his body with heroin. The opioid molecules streaming through his blood created a high that his brain jumbled with sleep. Overwhelmed, his respiratory system had ceased functioning: his lungs slowed to one-sixth the normal rate, sucking in air just twice a minute, until they stopped working altogether. Devoid of oxygen, the man keeled over, hitting the ground face down.