It's about her intentions, based on what happened and her knowledge, not about the statistical certainty of death.The word "usually" is not the standard required to imply an intent to kill from a person's actions. The acts done must be "virtually certain" to cause death, it matters not that they would usually or normally cause death.
The medical experts have, after the questions from Mr Myers, stated quite clearly that death from an air embolism is not a virtual certainty as the likelihood of death is dependent upon the volume of air involved and the time taken to administer it. Indeed, they have specifically contradicted Myers when he said that recovering twice is "inconsistent" with an AE. He obviously stated that because he knew they would contradict him and, in doing so, they have confirmed that recovery is consistent with an AE. Hence, death is not a virtual certainty.
Happy to disagree with you and move on.