When one firefighter is seriously hurt a ripple is felt throughout the FDNY — but Tuesday it was more like a wave. Three firefighters were critically injured in a massive inferno that ripped through five buildings in the Bronx. Officials say more than 170 firefighters responded to the fire which broke out at about 12:30 p.m. Tuesday in a two-story building on East 235th Street in Wakefield. Fire marshals say it was caused by children playing with fire on a stove top. No one inside the building at the time was hurt. The fire spread to four other buildings before it was brought under control about two hours later. Fire officials say 34-year-old Patrick Morello collapsed after suffering a severe heat stroke on the roof of a building while trying to put out flames. "The doctors had to bring the body temperature down, the man's temperature was extremely high," FDNY Commissioner Daniel Nigro said. Fifty-one-year-old Joseph Brady suffered what was later determined to be a heart attack. Doctors were working to save 44-year-old Sean O'Rourke's arm, which was nearly severed when the fire truck he was driving crashed while en route to provide back-up support.