While he's on the lam, Oskar decides there's no point in pinching pennies. He buys himself a first class train ticket and travels all the way from Germany into France.
Interpol agents are there waiting for him. They make the arrest, and Oskar's quickly convicted of the murder of Sister Dorothea.
Because he's presumed insane, he goes to an asylum instead of prison.
Oskar ends his story by mentioning that he's about to have his thirtieth birthday. People around him are saying that there's a new suspect in the Sister Dorothea murder, and that Oskar's name might be cleared.
Oskar's not all that happy about this, since he's not keen on rejoining the normal world. After all, he has everything he needs inside the asylum.
In his final sentences, Oskar tells us that he feels as if the world is calling him to do more with his life. He compares himself to Jesus once again, saying that when Jesus reached thirty he went out to gather disciples. At least that's what Vittlar tells him.
But for Oskar, it's hard to feel as if there's anything in life really worth doing. He decides to end his long story by returning to the children's nursery rhyme about death that he's mentioned several times in the book.
The rhyme ends with the words, "Better start running, the Black Cook's coming! Ha! Ha! Ha!"
Oskar feels as if death has been hovering over him throughout his life, whether it's the loss of his mother, father, uncle, or mentor. Even his greatest accomplishments seem mocked by death. No matter what we do with our lives, we'll all die someday.
The closing laughter in the nursery rhyme just seems to suggest that the only way to respond to the certainty of death is to laugh. There will be plenty of time to be serious when you're dead.
And so we end with Oskar laughing and reciting a children's rhyme inside an insane asylum. It's like a Grimms' fairy tale.