Mike said that Spock wouldn't let Kirk save Joan Collins from getting killed. He was talking about the Star Trek episode City on the Edge of Forever. But it was McCoy who prevented her from dying and Kirk stopped him.
Original International Airdates:
Canada: February 20, 2013 on Bravo
Harvey: Do you know how we won World War II?
Mike: Yeah, Spock wouldn't let Kirk stop Joan Collins from getting hit by that car.
This is an allusion to the 1967 Star Trek episode, "City on the Edge of Forever." In the episode, McCoy travels back to 1930 New York City and inadvertently changes history. When Kirk and Spock travel back to fix the timeline, they are taken in and cared for by a social worker, Edith Keeler, played by Joan Collins. Soon, they discover that she will be hit by a car in a few days' time, and if McCoy saves her life, she'll become the head of a pacifist movement that delays America's entry into World War II, allowing the Nazis to develop nuclear weapons first and conquer the world. Kirk is forced to choose between saving one life and saving the world.