I agree it seems straight forward. If a species was able to increase it's mutation rate during times of environmental change, then they would be more likely to survive. Although mutation is a risky venture (only a certain number of mutations are helpful; most are not), during times of high stress - esp. if you are heading down a path to destruction anyway - the risks of mutation are minimal. So if your environment changes such that you are going to die anyway, mutate the best that you can via normal evolutionary methods. Just stop checking for errors so often. You, at that point, *want* errors. you *want* your offspring to be diverse as possible, just in case one of them is able to survive the env. changes you are facing. That individual can then increase its error checking, and slow it's mutation rate again. It seems perfectly logical and within the bounds of normal evolutionary theory to me.