I suppose the tie-in is simply that we hackers think differently from scientists. It's much easier for us to visualize a complex tree of logic than for people who are not accustomed to it. The second purpose of the anecdote was to illustrate that there is a complete lack of software testing knowledge within the scientific community, or even the recognition of the need for it. All of the "testing" they do is on production data. There is no unit testing anywhere.