Board Thread:The Reference Desk/@comment-10429682-20140403031456/@comment-24752348-20140406182126

This is an issue for me as well. I've continually struggled to figure out why the Reapers appeared when Rose saved Pete from dying. It couldn't have been a fixed point in time, because the Doctor tells her that the thing she changed will stay changed at one point in the episode. And when someone broke a fixed point in time (River not killing the Doctor) it created an alternate universe where all of history was happening at once. So...I think the Doctor once said that only specific people are part of a fixed point in time. And I think that Paul Cornell (who wrote Father's Day) may have collaborated with Russell T Davies about this, so I think that when Pete died they just wanted to highlight what would happen if someone did something like that. Sorry if it didn't answer your question, but that is what I think happened to the best of my understanding.