Excellence in teamwork is an essential part of achieving high levels of performance in the delivery of healthcare and in the promotion of patient safety across a range of disciplines. There have been numerous efforts to promote adherence to guidelines and evidence-best practice. Advanced cardiac life support (ACLS) refers to a set of clinical interventions for several life-threatening conditions. Adherence to ACLS guidelines maximizes the probability of successful resuscitation and minimizes the long-term consequences for the patient. However, adherences rates to guidelines are known to be low despite quality guidelines and significant investment in training. Part of the problem has to do with the fact that most ACLS teams spontaneously assemble based on the availability of personnel at a given time on a hospitable floor, thus presenting formidable challenges for training as a team. The objective of this study was to produce a taxonomy of resuscitation team behaviors that impact adherence to the ACLS guidelines. Towards that end, the guidelines were translated into sets of rules to develop a means for measuring adherence and to investigate the role of team behaviors in guideline violations. The mean adherence to rules was highly variable, but comparatively low. We describe problems associated with adherence to CPR rules, ventilation and medication administration. Specifically, rule violations could be explained by behaviors such as misplaced attention, lack of sensitivity to temporal constraints, lapses in communication and failed execution of a subtask. Some of these behaviors are arguably the product of individual skills and others reflect a lack of cohesiveness, leadership and situation awareness in the spontaneously assembled teams. The specific implications for training are explored.