He did. He brought his veteran friend with PTSD to a gun range, and the friend shot Chris Kyle because he got triggered by the gunfire lmao

Kyle had begun working with veterans after leaving the military. Routh's [the killer] mother, who worked at the school that Kyle's children attended, had heard of his work and asked him to help her son. He agreed to take Routh to a shooting range, which Kyle believed had therapeutic value.[6] Routh was a 25-year-old U.S. Marine Corps veteran from Lancaster, Texas. Kyle and Littlefield had reportedly taken Routh to the gun range in an effort to help him with his post-traumatic stress disorder (PTSD), which he suffered from his time in the military.[7][8] Routh had also been in and out of mental hospitals for at least two years and had been diagnosed with schizophrenia, although his stated motive did not involve any symptoms typically associated with the disability, such as hallucinations or delusions.[5]

On the way to the shooting range, Kyle texted Littlefield, "This dude is straight up nuts." Littlefield responded, "Watch my six," military slang meaning "watch my back."[9] Four months later, while he was in his jail cell, Routh shared with former Erath County Sheriff's Deputy Gene Cole: "I was just riding in the back seat of the truck, and nobody would talk to me. They were just taking me to the range, so I shot them. I feel bad about it, but they wouldn't talk to me. I'm sure they've forgiven me."

He killed each of them with different weapons lol. Switching weapons is faster than reloading