Far beneath the Israeli military headquarters in Tel Aviv, in a bunker known as The Pit, commanders were trying to make sense of reports of Hamas rocket fire in southern Israel early on the morning of Oct. 7, when the call came in. It was a commander from the division that oversees military operations along the border with Gaza. Their base was under attack. The commander could not describe the scope of the attack or provide more details, according to a military official with knowledge of the call. But he asked that all available reinforcements be sent. At 7:43 a.m.,...