Older usage of the word does not include amusing coincidences such as this. It used to be used to describe speech which intentionally meant the opposite of its plain meaning for humor or emphasis, such as sarcasm, or in dramatic context a situation where the audience has greater awareness than a character.
Words change and this is a meaning everyone seems to want I guess. I was just pointing out that once you go down this route, its pretty hard to differentiate between what is ironic or not because its a broad and subjective definition.
Your assertion does not make sense to me. Your definition is that the situation is ironic because a slightly broader statement of that situation is ironic? It sounds like you are just saying its ironic because it seems ironic. All that means is that it gives you a feeling which you associate with that word. The reason it seems ironic is that the unexpected outcome of a "life-saving" thing actually resulting in injury, is amusing, because it is the opposite of its intention. In fact almost every time something has a net positive influence on overall outcomes, there will be cases where some outcomes are worse. If you are shot and the surgeon goes to perform life-saving surgury, but it turns out you have an allergy to the anesthetic and it kills you, is that ironic? A doctor who was intending to save you actually killed you. I don't know about this definition but I guess its the one we're stuck with. I'll probably just call it an amusing coincidence though.