SEAL Team Operator Robert O'Neill's 400 career missions included attempts to rescue "Lone Survivor" Marcus Luttrell and abducted-by-Somali-pirates Captain Richard Phillips. It culminated in those famous three shots that dispatched the world's most wanted terrorist, Osama bin Laden. Now O'Neill describes his idyllic childhood in Butte, Montana; his impulsive decision to join the SEALs; the arduo…