Where I come from, that's called "gross negligence" and "endangering lives".
I don't know where you are so I can't comment on your local laws. In the United States, it would likely be considered neither. Acts necessary to save human lives are neither criminally prosecutable nor subject to civil litigation.
The important word in that phrase, of course, being "necessary." Here's how a judge would evaluate your affirmative defense of, "Your honor, I had to drive like a madman: I had a man in obvious cardiac distress in the back of my car."
- First, did you have a reasonable belief the person was in extreme cardiac distress? "He was clutching his chest, short of breath, complaining of chest pains and having trouble remaining conscious. Okay, yes: the driver had a reasonable belief this individual was experiencing a life-threatening medical event and timely treatment was necessary."
- Second, was your action reasonable in light of the other options which were immediately available to you? "The defendant didn't bother to call an ambulance... then again, we *are* living in Detroit, where the response time to an emergency call hovers around one hour. His options were to either bring the guy to the hospital in his own vehicle, or attempt to provide cardiac care right there in the apartment. Transportation seems like a reasonable choice."
- Third, were unnecessary risks taken? "Sure, the guy was barrelling down Jefferson Avenue at 80 miles an hour. That was necessary. If he'd taken a detour and gone 80mph down a side street to hit a 7-11 along the way to buy a Slurpee, that would've been unnecessary... but he didn't do that, or anything like that."
- Fourth: if there was a reasonable belief someone's life is in jeopardy, if your action is reasonable in light of the options available to you, and if you avoided unnecessary risks, then brother, you are protected.
I am generally not a fan of urban driving. I own a Mustang GT and I go to the speedway whenever I can to race at high speeds in a controlled environment, but once I'm on public roads I obey the speed limit and I live in mortal fear of Suzy Homemaker in an SUV who's jawing on her cell phone instead of paying attention to her lane merge. I welcome the development of automated driving: for 99% of people it will be a massive step up in safety.
But let's not pretend that driving at 80mph in response to an immediate threat to a human life is something that we need to condemn. Those drivers amount to such a vanishingly small fraction of all accidents that I'm happy to give them a free pass. Go with God, may your tires have good tread, and I hope your passenger makes it.