I'm sorry, but nobody knows how they will react to a crisis until it happens - family or otherwise. Yes, we'd all like to think we would support our loved ones and at the same time do the right thing, but in reality, we have no idea how we will behave. And if it does happen - the 3am phone call - there may be precious little time to take it all in and think through a course of action that makes sense as the disaster unfolds, especially if it's your precious child who needs you to save them NOW and please Mum/Dad don't tell anybody just GET HERE - how can you think in a measured and logical way when that hits you out of the blue?
I have a little experience in this, and believe me, as a parent you don't think of your ingrained values or how you should behave as a moral citizen, you just know your kid is in deep trouble and they need you stat, and off you go, trying not to drive like a lunatic but that little voice in your head is saying, hurry, hurry, hurry, don't get there too late, and you remember stupid things like their first words and how they looked in the crib after they were born and why didn't you tell them you loved them more often, and at the same time thank the gods that they called you first.
It's an awful shock to the system, and we don't always behave as we would like to, but that's human isn't it?