Four days after the Boston marathon bombings that killed three people and wounded at least 264 others, Tamerlan and Dzhokhar Tsarnaev were on the run, essentially shutting down any and all activity in Boston, as authorities tried to track the brothers down. After numerous gunshots and pipebomb explosions, the chase ended in a dramatic gunfight that lasted almost 10 minutes. During this time, Tamerlan walked within 10 feet of other officers exchanging fire. When he ran out of ammunition, police tried to apprehend him, but an injured Dzhokhar ran him over, killing him, while escaping in an SUV. Almost 12 hours later, he was captured. According to newly released documents, he experienced extensive injuries, during the chase, including a gunshot to the face.

According to court documents, the 20-year-old Tsarnaev experienced multiple gunshot wounds, including one that appeared to enter through the left side of his mouth and exit through the lower left side of his face, according to CNN.

“This was a high-powered injury that has resulted in skull-base fracture, with injuries to middle ear, the skull base, the lateral portion of his C1 vertebrae, with significant soft-tissue injury,” Stephen Ray Odom, the trauma surgeon who treated Tsarnaev after his arrest, said in a testimony three days later. “As well as injury to the pharynx, the mouth, and a small vascular injury that’s been treated.”Tsarnaev was also suffered “multiple gunshot wounds to the extremities,” which were treated with bandages and pain medicine.

Tsarnaev was extremely lucky, depending on how you look at it, to avoid death from his wound to the face. Gunshot wounds to the head have a fatality rate of 90 percent. A bullet crushes a person’s tissue when it makes contact. It creates a hole that expands, considered a temporary cavitation wave, and then recoils once the bullet has passed through. The remaining hole is called a permanent cavity. Handguns are considered medium velocity weapons, and therefore produce less destruction than rifles or other military weapons, according to EMSWorld.

Tsarnaev is currently being held in Fort Devens, Massachusetts at a prison medical center where he is awaiting trial. He appeared in court last month to plead not guilty to 30 charges, including killing four people — one of them a Massachusetts Institute of Technology police officer who was ambushed a few days after the bombings. During his appearance, his face looked swollen and his left arm was in a cast, according to The Guardian. If convicted, he could face the death penalty or life in prison.