"About this time there occurred a strange incident which hardly anyone was able to understand. One night at about twelve o'clock there was a loud crash in the yard, and the animals rushed out of their stalls. It was a moonlit night. At the foot of the end wall of the big barn, where the Seven Commandments were written, there lay a ladder broken in two pieces. Squealer, temporarily stunned, was sprawling beside it, and near at hand there lay a lantern, a paint-brush, and an overturned pot of white paint. The dogs immediately made a ring round Squealer, and escorted him back to the farmhouse as soon as he was able to walk. None of the animals could form any idea as to what this meant, except old Benjamin, who nodded his muzzle with a knowing air, and seemed to understand, but would say nothing." In at least 150 words, explain how Orwell uses irony in this excerpt.