It's stated in the passage that the prisoner …….

The prisoner ran to his bed, taking his snow-covered coat off his shoulders as he went. He threw the coat onto his bed, together with his gloves containing the knife. He felt inside the mattress — the bread was still there! It was a good thing he had hidden it. He ran outside again and was able to get to the dining room without meeting a single guard, only a few prisoners arguing about cigarettes. Sitting down in relief to eat his soup, he knew that if he had been caught with the bread and the knife, he would have been placed in a cell on his own for ten days with no hot food.