An unseen dog remotely overrides Lucia's body in brief bursts and is the true target Florin says must be captured.
Jill's disclosure indicates the dog is part of the mechanism trapping or controlling multiple children inside Lucia Mar. Distance limits its influence to short bursts, matching the instantaneous personality switches seen in the ballroom and during Donut's earlier fight.
Florin insists the coalition protect Lucia and get the dog. Once it is removed, the remote control should end. Alexandro is also connected, but the dog's physical capture is the immediate actionable objective.
The dog replaces Lucia as the coalition's designated target and key to freeing the children.