When Thor repeated her words, Idun's attention was brought steadily to the god, gaze unwavering. She wanted to look away, but she couldn't. She was waiting. Waiting for him to say more, for Thor to react beyond simple repetition. They were not close, but Idun knew him. She knew Thor through her husband's love and admiration, through the glorious stories he told of his brothers. Perhaps she cared from a distance that made this concern seem sudden, like an invasion, but that had never been her intention. Idun had never not cared for Thor.
She didn't realize she was holding her breath until Thor wheeled around, anger and accusations startling her enough to force the exhale of that held breath. Beyond that, though, Idun knew better than to react. Calm was the key here. Thor was hurt, he was crushed beneath the actions of his wife, consumed by her betrayal, and Idun had no right to criticize his manner of handling that. With that much emotion swimming through him, of course he was going to snap. She'd put herself in his line of sight. She was a target.
Unless she stayed calm. That was always a good trick. Nothing defused irrational emotion quite like a rational reply.
"I knew nothing, Thor. I had no part in what has happened. Bragi just told me." It was a very calculated sort of explanation, each word weighed and measured and coated against sparks. If there was nothing to ignite, there was no way to start a fire. A neutral reply made her feel uneasy, but it was necessary. He was too angry. He was looking for a fight. Idun wasn't going to give him one.
"Would you like me to go?" she asked. Idun hoped the question would take him by surprise. He shouldn't be alone, not right then, but knowing that wouldn't do her any good unless he was struck over the head with the realization that he needed company. He needed someone.