I'm sure you're correct. I just know that one can be held criminally liable for beginning first aid and then stopping either a) until help arrives or b) until one is physically exhausted and can no longer carry on. If a person doesn't begin aid, then he/she is not liable. And to begin aid, you merely have to initiate contact.
For instance, you see a guy knocked out and lying face down on the train tracks. You go to turn him over and realize it's the guy that your wife had an affair with. If you then turn around and say, "Screw this guy", you are criminally liable (not simply because of the malicious intent, I only used that for an example) because once you took action by touching him or whatever else that might constitute "involvement", you assumed responsibility.
"Help" - in the form of a formal rescue crew - would not arrive in this situation. Ever.
"Exhausted" is the constant state of anyone in that location. Everyone there was technically dying. The risk in continuing as planned was bad enough (considering the number of bodies up there); the risk in trying to rescue someone was worse. Considering that the easier option already had a non-trivial fatality rate, that means a rescue attempt would likely result in more dead. Losing 2 to save 1 (instead of losing 1) is a romantic notion, but not realistic.
"Can no longer carry on" in that location means certain death - not to be confused with what you're thinking of, which is typically room temperature with plenty of oxygen in the vicinity of healthy passers-by with relatively easy access to communications and transportation.
The tort you refer to simply does not hold when the obligatory rescuer is himself at severe risk of death while attempting the rescue. If someone is trapped in a burning building, and you make one failed attempt to save them, you are not obligated to keep running into the flames.