I'm curious to know where this sudden "Oh, all the pilots out there thought helicopters had a 30 minute run dry capability" came from? Is there a serious suggestion that Joe line-pilot sits and reads FAR Part 29 in the crewroom, maybe with a bit of AC29-2C for bed-time reading? Unless your RFM specifically states a period within which to have landed (like the EC-155 25 minutes I quoted earlier) assume nothing. Assume the RFM means what is says:
Land immediately — Continued flight may not be possible. Ditching or landing in hazardous terrain is preferable to continuing flight.
The moot point is the oft-quoted Fire Warning, and the sad thing about that, in this context, is that it can result from a single point failure, and is often spurious, so that tends to lead to a suspicion of the instruction to Land Immediately. Most other situations are the result of more than one indication, usually independant of each other (switches plus pressure transducer, for instance.)
Human nature and self preservation will generally dictate looking for signs to confirm that things aren't as bad as we think, and the more clues we see to confirm that, the happier we feel with continuing. It's self induced "risky shift." It's not a helpful trait, but it's a fact.
One of the by-products of improved reliabilty and reduced accident rates in the offshore sector - don't believe me? then check the UK AAIB archives for the 1980s and 1990s - is we are less exposed to either first hand accounts or writen reports. Maybe that has eroded some of the sense of danger we should all feel when confronted by these situations? A classic Catch 22!