Detective Hassan Hamdy made the split-second decision to fire a single fatal shot at an unarmed motorist during an early morning traffic stop on a highway in Queens because he thought the driver was reaching for a gun, according to the detective’s lawyer. The driver, Noel Polanco, 22, did not comply with Detective Hamdy’s orders to put his hands up, instead reaching “down in a quick motion, down on the floor of the car,” said lawyer Philip Karasyk, representing the detective. Detective Hamdy twice yelled “Police!” and was wearing a heavy vest with the word “police” written across it, Mr....