Lance Halloran was the owner of the Mostly Colt gun store. Lance was present in the store alongside L.J. and Captain Henderson when Nemesis appeared. He died when Nemesis sprayed the store with gunfire, killing everyone inside except for L.J.
Trivia
Despite being listed in the film credits of Resident Evil: Apocalypse being played by Chris Benson, Halloran is not present in the film itself and it can be assumed his scenes were cut. He however is present in the novelization.