Why did Barty Crouch Jr. run of of Polyjuice Potion at the end of the movie Harry Potter and the Goblet of Fire?
I mean, it takes literally weeks to prepare, as we've seen in Harry Potter and the Chamber of Secrets, and we know that Barty Crouch Jr. stole supplies from Snape's storage. So he should have a cauldron of potion ready throughout the full year.
So how is it possible that he was so short of Polyjuice Potion that, literally five minutes after Harry came back with the Portkey, he couldn't drink another sip?
You will tell me that he thought that Harry will be killed by Voldemort, thus he doesn't have to hide, but:
He still needs to escape from Dumbledore and the others wizards in Hogwarts.
If he thought that he would be successful, he would've gone to the cemetery to be with the other Death Eaters.
I have no logical explanation.