While Isdis and her maids were busy dealing with complicated matters of the kingdom, Arad and Alcott's team were busy going around the whole castle, checking everyone's magic.
Merlin was efficient but a bit slow, so it was taking time to be absolutely sure they didn't miss anything. It might've only taken a minute to inspect someone's magic, but with hundreds of people in the castle, that was going to take hours when adding in travel time.
Searching for the drakainas had started the way Arad expected it: chaotic, but it then quickly calmed down and turned into a boring series of inspections. It was nothing like he expected to be slowly going around his own castle trying to find two drakainas.
Alcott told him that it usually isn't the case. Most dragons can get pretty aggressive once they sniff that someone is searching for them. Most of the time, it is the Metallic Dragons who are in hiding, but that doesn't mean they won't kill anyone.