Although Young's decision to eliminate himself from the lottery seems a noble decision, he really has no other choice. As the military commander, it is his responsibility to stay with the bulk of the crew, not letting them perish alone while he abandons ship; he takes himself out of the lottery because he has no other choice.
The crew's other nominal leaders, Dr. Rush and Camille Wray (Ming-Na) disagree with Young's lottery decision, believing that the survivors who transport to the planet would have a better chance of survival if Young exerts more control on the selection process.
Wray, a politician, and official of the IOA, believes that Young should hand-select those that will be sent ahead to the planet. The people with the necessary survival skills will lead to a better outcome on the planet's surface, and she believes Young's choice is a cop-out, and a refusal to do his job as commander. Young will hear nothing of Camille's argument (perhaps it hits too close to home for him).
Threatening to take her name out of the lottery entirely, he warns her to leave the subject alone. For what it's worth, I think Camille has a point, but she backs off, not wanting to press Young further, lest he makes good on his threat. Her reaction enlightens us about her leadership qualities as well; she is not especially courageous - a weak leader. It's a significant reveal given events later in season one.
Young's refusal to take responsibility for selection feeds my sense that he has lost his taste for command (something that only grows as time goes on), and perhaps that he really isn't fit to lead the survivors and make the sometimes hard choices.
Rush's reaction during the entire episode is fascinating, as he is much chastened since his breakdown in "Darkness." Perhaps the weight of the unforeseen consequences resulting from dialing the Ninth Chevron has softened him. His attitude throughout "Light" is conciliatory, even with Young.
Like the colonel, Rush has removed his name from the lottery. But his motives are different, and much more personal. Going through the Ninth Chevron gate has been his life's work, something that has cost him greatly and very personally. It is, as Rush says, his destiny to be aboard the ship, and to die aboard her makes more sense to him than trying to survive "on a rock with a bunch of strangers."
The relationship in this episode between Rush and Young takes on an interesting new dimension. I believe that Col. Young finally realizes that tinkering with the ship's systems without Rush's input had been foolish. While Rush had been trying to understand the ship's systems and power needs, Col. Young had been allowing personnel to push a lot of buttons, and ultimately to make the power-draining move of dialing the ship's stargate.