At the end of the movie we are shown
a bowl with berries in it and Seneca Crane looked like he was locked in a room with them and was supposed to eat them. Did he eat them?
Why did that happen?
Seneca Crane, the Head Gamemaker, was the one responsible for producing the Hunger Games. He's the one who thought of the trick to announce two winners, and then withdraw that rule, to further excite the viewers. But when Katniss bluffed her way out of the games with the poisonous berries, he was humiliated - him, and worse, President Snow.
Since Snow isn't the kind of man to take humiliation lightly, someone had to accept responsibility - and punishment - for the debacle. Locking him in a room with the same poison berries is Snow's way of telling Crane: "You'll be taking your own life, taking responsibility for the fiasco, and thus shifting it away from me".
Did he eat them? I don't think he had a choice.
If you want a more canon reference, you can find it in the second book, Catching Fire, where President Snow says
"If the Head Gamemaker, Seneca Crane, had had any brains, he'd have blown you to dust right then. But he had an unfortunate sentimental streak. So here you are. Can you guess where he is?" he ask.
I [Katniss] nod because, by the way he says it, it's clear that Seneca Crane has been executed.
Seneca didn't have a choice. They were the only source of food in the room and he was locked in there. Catching Fire reveals much more about it, but I won't spoil that much for you.
President Snow didn't want to take responsibility for the poison-berry part at the end of the games, so he punished Seneca Crane instead by locking him into a room with the same poison berries where he would die from starvation or from the berries.
I believe at one point in time in the book it said that Snow actually did hang Crane after that. Either way, President Snow didn't want to take responsibility so Crane did.
That room and the berries were Seneca Crane's execution. His only choices were to eat them and die quickly, or die of thirst and hunger.
The berries were Nightlock, a fruit that will kill you in seconds after eating it. They are what killed Foxface, and what Katniss and Peeta were going to use at the end of their games as a double-suicide, if Crane hadn't intervened and allowed them to both be the victors.
President Snow hadn't liked the fact that Katniss and Peeta were going to kill themselves, nor did he like that they both won. However, he couldn't exactly kill them without an uprising and full-scale rebellion, so he executed Crane instead.
He was the game maker of the 74th Hunger Games and at the end, as you probably know, he was the one who announced the two winners. He and Snow were both humiliated. He was executed by Snow by being locked in a room with the poisoned berries, the only source of food. He had no choice. It was either eat the berries or starve. Either way he would die.
Seneca crane was locked in the room with only a elegant bowl full of night lock berries. Snow left that as a note, telling him that he could commit suicide or they could take his life. it didn't tell you what he chose but it was certain he died.
Seneca was order to be locked in a room by the commandments of President Snow as consequence to allowing Katnis and Peta to leave the hunger games both alive. In the room in which Seneca was locked in there was a crystal glass bowl holding some of the same Night Lock berries Katnis and Peta threatened to kill themselves with. The berries obviously stated out the message "succeed taking your own life or succeed dying to try to live" from President Snow, if he choose to eat the berrie is unknown but either way…
President Snow is a bastard.