Van Helsing uses dawn hypnosis to let Mina sense through Dracula's blood-bond without surrendering her waking will to him.
Because Mina Harker and Count Dracula share a coerced blood bond, Van Helsing hypnotizes Mina at dawn when the vampire's power changes with the day. Her conscious voice recedes and she reports sensory fragments from Dracula's surroundings.
The first session yields water against a hull, hurried feet, and a capstan chain, proving Dracula has fled aboard ship. The method transforms contamination into a directional advantage while requiring careful timing.
A quiet induced trance in which Mina lies or sits with closed eyes while Van Helsing questions her at dawn; no apparatus is required.
Hypnotism is the hunters' means of extracting intelligence from the blood bond without waiting for Dracula to issue commands.