There's another myth that in life or death situations our survival instincts kick in and overpower whatever values we have. For instance if one was on an abandoned island with a loved one, perhaps that love wouldn't count for much when that person got really hungry.
Both myths undermine the role of our explicit, chosen values.
The first myth first. The idea that we reveal our true self in a life or death situation is nonsense. In life or death situations, if we act unpredictably, it's because we're panicked. People who are that panicked make rushed decisions. These decisions come out almost random, in that they easily could have gone in a different direction. Indeed people often find somewhat inconsistent behaviour in moments of pure panic.
For the second myth, similarly the idea of 'survival instincts' turns out to be somewhat misleading.
A good way of illustrating this point is by looking at what *really* happened on the Titanic. On the real Titanic on ratio, more Americans survived than British people. Why? Because the British people queued for the lifeboats, and the Americans pushed in. I know, it'd almost be funny if it wasn't such a tragic event. But the bottom line is that, even in such dire circumstances, their cultural values defined them.
In life or death situations we do not escape who we are in terms of the values we have chosen for ourselves. If we do, it is only because we are too panicked to think clearly and act in an almost random way.
There is no truer self than the values we choose to live by day-by-day.