You have to appreciate the opening line: "It has come to my attention….."

So here's the breakdown:

Rand Paul asks “whether the president has the power to authorize lethal force, such as a drone strike, against a US citizen on US soil.”

Holder responds "It is possible, I suppose, to imagine an extraordinary circumstance in which it would be necessary and appropriate…"

Rand Paul freaks out and filibusters, asking a different question: "Does the president have the power to use a weaponized drone on an American citizen not engaged in combat on American soil?"

"No".