(Above) Firefighters line up as the body of Capt. David Rosa is transported from St. Mary Medical Center to the Coroner’s office in Los Angeles. (Below) Dr. Mauricio Heilbron Jr., a trauma surgeon at St. Mary.

The day after Long Beach Fire Department Capt. David Rosa was shot and killed, St. Mary Medical Center was, in the words of trauma surgeon Dr. Mauricio Heilbron Jr., “a building that was sad. A palpably sad building. Sad, pained and scarred.”

I talked to Heilbron Tuesday morning. It wasn’t an interview. I asked him what happened; that was my sole question.

“There’s a lot out there in the news and on social media,” Heilbron said. “But it doesn’t show the warts, it doesn’t show the pain, it doesn’t show the blood on the floor.”

Heilbron said he got to St. Mary at about 8 a.m. Monday, after the “acute” phase, after Rosa was pronounced dead.

“The trauma surgeon gave his all and the team did everything they could to keep him alive and they didn’t do that, and now there was another guy to work on (the as-yet-unnamed civilian who was also injured at the scene and was transported to St. Mary).

“The surgeon was just spent. I sent him home and got to work. We didn’t know what was going on. There was so much chaos. We didn’t know if this guy was the shooter, but the police were concerned that he was. A social worker came in and asked me to talk to his wife, who had witnessed her husband getting shot by the (shooter).”

Heilbron said he saw a photo on the Post’s website, and thought he looked familiar.

“I thought, ‘Oh my God, he really looks familiar.’ I’ve been doing this for 20 years, and I’ve lived in Long Beach for so long and I didn’t know if I knew him from him bringing people to the ER or if I just knew him from the coffee shop.”

Heilbron is a daily customer at It’s a Grind on Spring Street.

When patients come to the ER as trauma patients, physicians get a heads-up from EMTs. The EMTs are met in the ER by a slew of hospital staff: doctors, a trauma surgeon, two to six nurses and various technicians. “It’s organized chaos,” Heilbron said.

When a firefighter or police officer is brought to the ER, “the whole tension gets ratcheted up to a degree that’s difficult to explain.”

Rosa, he said, came in clinging to life. Men and women in scrubs did “literally everything” they could from the time he entered the hospital until he got the operating room.

“A lot of what they do is heroic, not in the hero meaning, but doing literally everything they could,” the physician said. “Some of it’s horrifying, some of it is invasive and not very pretty, but everybody’s brain was in lockstep. When that’s going on, 30 seconds can seem like 30 hours and two hours can seem like two minutes. Time gets really freaky.”

While Rosa’s body was still at the hospital, fire and police personnel began showing up in large numbers, Heilbron said.

“Everyone saw the procession when Rosa’s body was being transported, but what people didn’t see was inside the hospital. There were hundreds of firefighters and some police and medical people lined up along the hallways standing at attention. The line went all the way down the hall, down through the lobby all the way to the car that took him away. It was such a display of respect and unity and fellowship.

“I can only imagine the pain they felt bringing Rosa to the hospital. The people who brought them in were doing their job, but their job was their captain. I can’t imagine it. I can’t even think of the words.

“Seeing those people all lined up was just an overwhelming sign of respect and grief and loss and, in a weird way, love,” said Heilbron.

“It was something that I’m never, ever going to forget. Nobody in the hospital will forget it, either.”