Lakshman and Urmila did wat they cud do to the maximum for doing their duties. They are the best example of the extreme extent that one can go to perform or do something that one desires from heart. However, it is not always the desirable results that we get despite givin our heart and soul to the action. And dats wat wen the sayin gets its value 'wat to do, it's destiny'
However, I get your point of wat u want to convey dat despite their bestest efforts includin even goin against prakrati, both could not stop to wat all happened to SiyaRam. But dats again destiny.
Today, human beings know they are destroyin the nature, which in turn is leadin the nature to ecological imbalance. Nature shows its anger from time to time in the form of earthquake, volcanoes, Tornado, drought, floods, and the list is endless.
As said here in one post 'things are gonna happen the way God has designed them to be', God is takin the life on earth to its destiny. May be it is already decided that human race is gonna always act like this and this will in turn in lead to destruction and again the cycle of life will start from the beginning. We go against nature and we compensate as well (in the form of planting trees and risin awareness) to balance out the damage we are causin just like Lakshman did. But, watever balancin we are tryin, there is no denyin the fact that nature is gettin disturbed. Watever God wants to make the life on earth comes full circle, it is happening any way.