So I think Manny and Beth-Ann have it spot on. Peter Rabbit dies in this book, and his escape is a moment-of-death fantasy. Peter is the Peyton Farquhar of kids books. 
 Farquhar, for those who don't remember, is the Alabama Confederate (gentleman farmer / non-combatant) from Ambrose Bierce's An Occurence on Owl Creek Bridge. He's strung up to a railroad bridge to be hanged by the Union soldiers, but his rope breaks and he pulls of a miraculous escape, only to have his escape end with him still on the rope as he chokes to death. 
 Well, little Peter doesn't have Union soldiers to string him up, but he has old Mr. McGregor to chase him around the garden, and in Peter's attempt to escape he dives into a watering can -- and I say he drowns. How's that for a cautionary tale? I figure that Peter's death in the watering can is also a euphemism for rabbit stew, and Peter becomes a yummy dinner for Mr. and Mrs. McGregor. Lucky farmers that they are. 
 But Peter, at least, is able to enjoy a moment-of-death fantasy where he goes home and declares to Mother Rabbit that he's learned his lesson. But even at home, even in his fantasy, death begins to close in, and while his siblings play and the smells of cooking rise up to greet him (Mrs. McGregor's kitchen as she skins his corpse, perhaps?), Peter ends his day (and his life) wrapped in the blankets of his little bed. Shivering from the cold he caught in the Mr. McGregor's water bottle. 
 Death comes to us all, little bunny, especially when we ignore our parents! Remember that. 
 Culinarily, I think I need to get my own little rabbit for a stew. It's been a while, and rabbit is de-lish.