It ends when I want it to end... if i decide to take 5 mill, i will do as i please.
decide to take 5m?? if your auction starts at 5 and someone bids 5, why in the world would you not take it?
if someone bids 9m they should feel free to not give 9m just as you are in that case.
this is why such auctions fail often without clear rules and reliable buyers/sellers