You sneak away to go fight a battle:

Merlin:
He came after you and used magic to save you. You of course were fine, but he was extremely worried.

Arthur:
He left the castle as soon as he could, despite his fathers wishes. You were his love and nothing would stand between him and you.

Mordred:
He freaked out and tried to figure out where you went. When he did he went after you as soon as possible.