This paper presents qualitative findings from an experiment designed to investigate breaks in presence. Participants spent approximately five minutes in an immersive Cave-like system depicting a virtual bar with five virtual characters. On four occasions the projections were made to go white to trigger clearly identifiable anomalies in the audiovisual experience. Participants' physiological responses were measured throughout to investigate possible physiological correlates of these experienced anomalies. Analysis of subsequent interviews with participants suggests that these anomalies were subjectively experienced as breaks in presence. This is significant in the context of our research approach, which considers presence as a multilevel construct ranging from higher-level subjective responses to lower-level behavioral and automatic responses. The fact that these anomalies were also associated with an identifiable physiological signature suggests future avenues for exploring less intrusive ways of studying temporal fluctuations in presence during the course of the mediated experience itself. The findings also reveal that breaks in presence have multiple causes and can range in intensity, resulting in varying recovery times. In addition, presence can vary in intensity within the same space, suggesting that presence in an immersive virtual environment can fluctuate temporally and that spatial behavior is consistent with what would be expected in an equivalent real environment.