The Doctor swallowed at the Master's words, but the hand holding the gun didn't waver.
"My Jack died twice because of you," he said, in a voice that was distant and icy cold and didn't sound like his own. "Add to that Jack dying here, and the Master - " His voice shook for a moment before he got it under control. "Four deaths, Master."
His eyes blazed and his fingers tightened again round Jack's gun. "How many more times can you afford to die?"