Flashback

"He was a short, slender young man of about twenty. I was afraid of him-afraid of something-and as he passed me on the trail I threw a grenade that exploded at his feet and killed him. Or to go back: Shortly after midnight..." Page 125

This passage seemed kind of weird to me. Basically the whole book is a series of flashbacks. O'Brien constantly flashes back to his life during the war. These memories are not necessarily in chronological order. But this passage is different. The chapter starts as a flashback of O'Brien talking to his daughter, but it switches to a flashback of the war. He even sets up the flashback with the phrase 'Or to go back'. This seemed odd to me. During the rest of the book, his stories had no intro. The reader was immediately engulfed in the memory. However, this memory was perhaps more sensitive and needed an intro. It still seems odd to me.