A runaway cab jumped the curb near Rockefeller Center in Manhattan on Tuesday, severing the leg of a British tourist who had been eating a hot dog with friends and family.

The cab, which may have been trying to avoid a bicyclist, plowed into the 23-year-old woman as she was crossing 49th Street shortly after 11 a.m., New York TV station WNBC reported.

Nearby pedestrians quickly sprang into action.

Among them was TV personality Mehmet Oz, better known as Dr. Oz, who examined the cabbie and helped a plumber apply a tourniquet to the woman's mangled leg, according to the New York Daily News.

Two other people were injured in the wreck and taken to local hospitals.

"People rushed over to the woman with bottles of water," eyewitness Louis Burgdorf, 27, told the Daily News. "It was amazing. No one was afraid to come in and assist immediately. If this woman survives, it is because people rushed over so quickly to help. It was crucial."

No word yet on whether the cab driver will face any charges.