I was tormented by the question about this for a very long time... on leaderboard, I see runs where as soon as at 6 am runner immediately restarts game. I think this is wrong, because screen "You did it!" shows you, that you beat night and after this screen appears challenge's star

I don’t know how it happened that I asked the question just now

It literally says in the rules that the run ends when it says 6 AM on the last challenge, so obviously that means you can just exit out of every other challenge as soon as it says 6 AM.