After Brock accepted the duel against Morgana, the man came down the stairs from the jarl's mansion and stood face to face with the trickster.
They were both the same height, so their eyes met at the same level as Brock smiled mischievously, and Morgana kept a calm but vicious stare.
"You brought your own audience, I see…" said Brock as he gazed at the married couple and Sif, who was further back with Corinna.
"They are just here to watch. Don't worry about them…" Morgana replied without taking her gaze off the man.
In Aegis, when two people agreed to a duel, and their fight commenced, other people weren't able to interfere in the battle.
If two people were dueling and someone tried to heal their friend who was losing, the spell wouldn't have any effect as the other person was locked into the duel.
It was the same deal if someone tried attacking a person in the midst of a duel. The spells would simply disappear before reaching their target.