Nineteen firefighters were killed while battling Arizona's Yarnell Hill Fire on June 30. Among those killed were two local firefighters: Kevin Woyjeck of Seal Beach and Christopher MacKenzie from the San Jacinto Valley.
Brendan McDonough was serving as a lookout for the team when his crewmates were killed. He was a half mile away watching the fire behavior when the flames suddenly whipped 180 degrees around and cut off their escape route.
The 21-year-old says there's nothing he could have done except died with his team.
"I asked a million times, 'Why am I sitting here, and why isn't someone else? Why aren't they sitting here with me?" McDonough told ABC News' Brian Ross.
The interview was filmed inside the Granite Mountain Hotshots' station house, marking McDonough's first visit since losing the 19 firefighters who were like family to him.
Though five weeks have passed, McDonough said he still hears the cellphones that were ringing in the back of his fire truck.
"Whoever didn't bring their phone, I could hear phones ringing, knowing that it was their wives, their family," he said.
McDonough told ABC News that he is still processing the tragedy, saying "some days are better than others, some hours are better than others."
"Coming home, that was the worst feeling ever," he said. "Knowing that these families would see me, but not anyone else off that crew. No one. I was the only person they're going to see."
McDonough said he does not plan to quit firefighting. He has attended the funeral of all 19 fallen firefighters and visited each of their families.
ABC News contributed to this report.