In recent years, Danish hospitals have merged their emergency facilities into Joint Emergency Departments. This poses new collaborative challenges across traditionally separated specialized departments, which now have to collaborate in a shared environment. Despite established protocols and patient monitoring regimes, as many as 31 % of non-critical patients deteriorate with potentially severe consequences. To understand why this may be, we conduct a field study with the aim of investigating what factors external to patients relate to the clinicians' ability to notice adverse events. We look at the case through the lenses of common information spaces. In particular, we apply Bossen's seven-parameter framework to discover new dimensions of how Emergency Departments and individual clinicians identify and respond to unforeseen events, and how they handle the associated cognitive challenges. We complement these findings with a review of a novel taxonomy for patient monitoring. Our contribution is the identification of four improvement areas for patient monitoring platforms in terms of support for the identification of patient deterioration.