Sorry, how many runways are there at SYD? Last time I counted there were three (maybe six depending on how you look at it) so how does debris on one runway cause a diversion? Even if the debris was at the i/section of 25/16R which might close both, what about 16L (or 34R depending on the wind)?
Surely a triple at the end of a trans-Pacific flight would find 16L/34R long enough!!!!