It's the different methodologies that are hard to reconcile with each other. If the air embolism narrative is true then she perfected an inconspicuous, low risk method of meeting whatever Munchausen like need she was alleged to be fulfilling - almost ingenious really. The insulin cases (or at least this one) could be seen as a calculated risk to divert attention by creating a problem when she wasn't there. It's the intentionally perforating the oesophagus, as she was alleged to have done with Child E, that borders on insanity in my opinion. If an autopsy were performed it would inevitably raise questions. If she, as Dr Evans suggested, intentionally inserted a surgical introducer to achieve, just imagine how this would look if a colleague walked in at just the wrong moment.
I think this is why the prosecution aren't pinning themselves down with a motive as has been the case with other healthcare serial killers:
Beverley Allitt: Munchausen's
Ben Geen: liked to play the hero
Colin Norris: hated old people.
It's helpful to seal the deal with the Jury to have a neat narrative, but they've eschewed that in this case because the narratives of the individual cases are just so chaotic.
