Inquiry on medical interactions demonstrates how the discursive construction of the clinical case affects diagnostic reasoning and treatment recommendations. Drawing on an ethnographic study in an intensive care unit, it is elucidated how this process is at play in a ward that adopts an extreme, guideline-divergent policy as to the use of antibiotics. The paper centers on how physicians assemble the case as ‘treatable’ or ‘not yet treatable’, and how in doing so they ‘talk into being’ two contrastive policies on antibiotics and position themselves toward the one adopted in the ward. The assay distinguishes the discursive resources shown by physicians to both project an infectious disease diagnosis and resist this treatment-implicative trajectory. It is asserted that the physicians’ contentious discursive construction of the case has vital consequences in the way the ward’s extreme policy is jointly accomplished as a highly reflexive process sensitive to the contingencies of any particular case.