Michelle Thomas, who runs The Three Horseshoes pub, told Sky News she heard two loud bangs that she initially "thought were fireworks" on the night of the shooting.
The suspect, who is believed to have known the victim, fled in a car that was found later on Friday night at a bridge crossing the River Thames in Dartford, 17 miles away.
Lisa Smith, 43, was pronounced dead in the car park of The Three Horseshoes on Friday.
Police, who discovered a gun inside the vehicle, said they were not looking for anyone else in connection with the shooting.
She described the aftermath, describing "so much commotion - screaming, shouting, crying" and adding the attack had left the community in "absolute shock".
