The moment Lucian left the courtroom, he went in search of his wife's brother to discuss with him other alternatives if the king decided to fight against him instead of standing by him. He couldn't take the risk of not having another way when he'd given them no choice in there.
Lucian went to the room given to Rylan, but the man wasn't in there. He found two maids cleaning the room and asked them about his whereabouts. They told him the redheaded man was in the courtyard with his wife.
He made his way to the courtyard, but even before he rounded the corner, he could hear Ave and his sisters' loud cheering voices and the clanging of swords. He couldn't help but wonder what was going on in the courtyard until he walked there and saw it.