A laser eye surgery system that has a patient interface between the eye and the laser system relying on suction to hold the interface to the eye. The patient interface may be a liquid-filled interface, with liquid used as a transmission medium for the laser. During a laser procedure various inputs are monitored to detect a leak. The inputs may include a video feed of the eye looking for air bubbles in the liquid medium, the force sensors on the patient interface that detect patient movement, and vacuum sensors directly sensing the level of suction between the patient interface and the eye. The method may include combining three monitoring activities with a Bayesian algorithm that computes the probabilities of an imminent vacuum loss event.