We present a research result of our project named Life2 Guard. The project aims at detecting a person facing a sudden physical disorder in private rooms such as restrooms. In this paper, firstly we specify the required functions for the system to detect physical disorders in private rooms, which are Privacy-Aware Sensing, High Availability, Quick Responsiveness and False-Call Avoidance. Secondly, we propose how we have implemented the system to fulfill the requirements using following key approaches: IR Sensor, Bayesian Network, Approximate Inference, Naive Bayes and User Interaction. In this way we have succeeded in detecting physical disorders such as faint or convulsion in a certain situation for 100% within about 30 seconds.