(CNN) An emergency medical technician raced to assist a colleague who had a stroke on the job, but he fell unconscious before he could help.

"We're not believers in coincidences, except for today," Fire Commissioner Daniel Nigro told reporters on Thursday. "And it is an extremely tragic coincidence."

Liam Glinane, 63, an EMT with the New York City Fire Department, was driving an ambulance Thursday on the Brooklyn Queens Expressway when he suffered a stroke and had a minor crash, city officials said.

He was alone in the ambulance and was not responding to an emergency.

Lt. Raymond Wang, another EMT, arrived on the scene to help and saw that Glinane was unconscious. But he suddenly suffered an aortic aneurysm before he was able to treat his colleague, Nigro said.

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