Scott, your question about emergence and diagnosis ...
Might it be that although the process of intervention - in mechanics - might be very specific, with little room for the luxuries of 'emergent thinking', the process of arriving at a diagnosis (and even tentative prognosis) might be of a different nature, and might involve tacit, fuzzy, decisions about not what specific interventions to employ, but what metaphors or homologies to employ in thinking about the diagnosis.
This reminds me (I hope this is pertinent) of a piece of research into mis-apprehensions in problem solving in science, in which the root of the mis-apprehensions was in the misapplication to either a calorific or a Brownian conceptualisation of heat, which led to 'bugs' in thinking through the problem, and that in turn led to an inability to think through a strategy to achieve the solution. It was only when the two frameworks were made explicit, and discussed openly, that both students and the teacher realised that the two frameworks / metaphors / models were appropriate to different kinds of context.