The recent upsurge of interest in the co-articulation of biopolitical and bioethical entanglements underpin both a concern for the putatively temporal thresholds of human life and the very conception of a bounded humanity itself. Taking a step further, I want to suggest that micro(chimerism) as a very specific form of somatic multiplicity, read together with the contemporary rethinking of the concept of immunity, instantiates a fundamental disordering of linear temporality. And that in turn calls for a further reconceptualisation of conventional bioethics. I acknowledge the force of an existing postmodernist bioethics that has attended to the materiality and viscerality of the body and challenged the meaning of human being but, until recently, it has not addressed the bookends of life and death. Once the teleology of the life course is contested, however, death is no longer an insult to being, but merely one event constituting an ongoing vitalism. I propose an atemporal bioethics of coexistence rather than one of successive existence that is faced always with its own finitude.