Realising the vision of pervasive healthcare will generate new challenges to system security. Such challenges are fundamentally different from issues and problems that we face in centralised approaches as well as non-clinical scenarios. In this paper, we reflect upon our experiences in the HealthAgents project wherein a prototype system was developed and a novel approach employed that supports data transfer and decision making in human brain tumour diagnosis and treatment. While the decision making needs to rely on different clinical expertise, the HealthAgents system leveraged a domain ontology to align different sub-domain vocabularies and we have experimented with a process calculus to glue together distributed services. We examine the capability of the Lightweight Coordination Calculus (LCC), a process calculus based language, in meeting security challenges in pervasive settings, especially in the healthcare domain. The key difference in approach lies in making the representational abstraction reflect the relative autonomy of the various clinical specialisms involved in contributing to patient management. The scope within LCC of accommodating Boolean-valued constraints allows for flexible integration of heterogeneous sources in multiple formats, which are characteristic features of a pervasive healthcare environment.