Kalisa Dixon was getting ready to leave her West Pullman apartment Friday afternoon when she heard screaming from the unit across the hallway.

Within seconds, a panicked mother flung open the door and tossed a baby into her hands.

“She ran out and basically threw me her baby, like ‘Take my baby, my [son] is on fire,’” Dixon said, describing the chaotic scene at a Far South Side blaze that left three children and their mother injured. “Then the little boy came out of the apartment literally on fire.

“He was taking his clothes off and then rolling back and forth to put the fire out,” Dixon, 43, said. “And he stopped and was about to get up and I said, ‘No, you’re still on fire. Roll, roll baby, roll baby, roll.’ And the fire was finally put out.”

That boy, about 12 or 13 years old, suffered severe burns in the blaze that was reported about 12:15 p.m. at a second-floor apartment in the 12100 block of South Indiana Avenue. He was taken to Comer Children’s Hospital in critical condition, according to the Chicago Fire Department.

The boy’s mother suffered burns to her arms and was taken to the University of Chicago Medical Center in fair to serious condition, authorities said. Two other children, including the infant, were also taken to Comer in good condition and were treated for minor smoke inhalation.

”He was burned from the top of his head down to his feet,” Dixon said of the boy who was on fire. “Blood was just gushing out. His whole body was just burned.”

Still, despite the life-threatening injuries, all he could think about was his mother.

”The boy was basically worried about his mom,” Dixon said. “He was like ‘The fire’s off, it’s OK, I’m OK mom.’”

When everyone was out of the apartment, the group realized the fire was too big to put out themselves. The mother and her kids rushed out while Dixon called 911 and went door-to- door telling residents they had to evacuate the building. Firefighters showed up about 10 minutes later, she said.

Two CTA buses soon came to the scene to give displaced residents, including Dixon, a place to sit and cool down. American Red Cross employees offered bottles of water to residents, emergency personnel and reporters gathered on the bus and the sidewalk.

The west side windows of the second-floor unit were burned out with the street blocked off to traffic as fire and police officials investigated. After more than five hours of waiting, residents were allowed back into their homes just after 5:30 p.m. Authorities hadn’t yet determined the cause of the fire, but foul play wasn’t suspected.

“It was like a state of shock [for me], the fact that he was on fire, running in front of me,” Dixon said. “I just hope that little boy is alright.”

Contributing: Luke Wilusz