A pediatric surgeon has died after diving into Lake Michigan to save two young boys.

Dr. Donald Liu, the chief pediatric surgeon at the University of Chicago’s Children’s Hospital was dived into the rough waters after seeing their family friends getting swept underneath the waves. Liu’s family tried to stop him from entering the dangerous waters, but he was focused on saving the boys.

“You couldn’t stop him,” Liu’s wife, Dr. Dana Suskind recalled. “He always did the right thing.”

After helping the boys, the pair were able to wade back to shore. Unfortunately, Liu was swept back into the strong currents.

“After he saved those boys and I couldn’t see him, they finally found him and they pulled him from the water. I tried to do mouth-to-mouth, but I knew. And it was so painful,” Suskind tearfully said.

Suskind and other rescuers were unable to revive Liu, who tragically passed after his heroic rescue.

Liu was a surgical oncologist who specialized in removing tumors in young cancer patients, and was an expert in Hirschsprung’s Disease.

“Everything [Liu] did, everything he talked about was always for the children,” said Jeffrey Matthews, the surgery chair from the University of Chicago Medicine. “And so the tragedy is that he died, of course, as a hero doing what he did every day, which was saving children.”

“He wore scrubs all the time. He would’ve gotten married in his scrubs if he could. He was so understated, but really such a huge stature,” Suskind said in memory of her heroic husband.

“I’m really sad that my dad died because every time he would come home from work at 5 o’clock, even though he didn’t have to, he would play baseball with me and we would go in the backyard,” Liu’s 10-year-old son Asher said. “We would always watch the White Sox together.”

Liu leaves behind his wife and three kids, Genevieve, 13, Asher, 10, and Amelie, 7. He will be buried wearing his University of Chicago surgical scrubs, and holding a White Sox baseball, a video game, and his children’s pictures.