Lt. Johnny Mercil became the latest member of the Minneapolis force to take the stand as part of an effort by prosecutors to dismantle the argument that Chauvin was doing what he was trained to do when he put his knee on George Floyd’s neck last May. According to testimony and records submitted Tuesday, Chauvin took a 40-hour course in 2016 on how to recognize people in crisis — including those suffering mental problems or the effects of drug use — and how to use de-escalation techniques to calm them down. Sgt. Ker Yang, the Minneapolis police official in charge of crisis-intervention training, said officers are taught to “slow things down and re-evaluate and reassess.” Records show Chauvin also underwent training in the use of force in 2018. Mercil said those who attended were taught that the sanctity of life is a cornerstone of departmental policy and that officers must use the least amount of force required to get a suspect to comply. Officers kept restraining Floyd — with Chauvin kneeling on his neck, another kneeling on Floyd’s back and a third holding his feet — until the ambulance got there, even after he became unresponsive, according to testimony and video footage.