The anger doesn't frighten him, though he knows deep in his heart that it should. She's not a snarling little dog in front of a mighty beast anymore. She's the beast and he's an impotent nothing... Except he isn't, so long as he's here. He's certain that this land won't forsake him if she insists on challenging him.

He continues down the stairs, walking right into the maelstrom of her anger, until he's standing a few steps above her, looking down on her. "And I thought we were well past all that these days." He's not surprised- it's really not that strange that something could trigger Regina's temper and make her despise him again, just as the converse is true. They define complicated.

"What exactly will all that accomplish? I think we've both learned that revenge never truly amounts to much. A few pounds of flesh won't buy you back those years." Maybe on another day he would have tried to apologize, but he's not feeling it right now. She came into his house and started throwing wild accusations- true as they may be- around. The rules of decency don't apply here.