The anesthesiologist who prescribed painkillers to Long Island pharmacy gunman David Laffer pleaded not guilty Monday to selling scrips to addicts and drug dealers. Prosecutors say Dr. Stan Xuhui Li, 57—who makes $400,000 a year as an anesthesiologist at a New Jersey hospital—wrote over 17,000 prescriptions, mostly for opioid painkillers, in the last 2½ years at the Flushing clinic he operated on weekends.