Doing one's duty properly

Sri Swami Vishwananda: It is said in the Gita [Bhagavad Gita] that whenever you do your duty, do your duty properly.
Even if it hurts somebody, it doesn’t matter.
That’s how it is for the soldiers.
When they go to war, they are serving their country and they are protecting their country, their duty is to serve and to protect their
country.
And they don’t create any Karma, even when they are fighting.

Watch here a video which tells the story from the Mahabharat about the 100 Kauravas and 5 Pandavas on the battlefield:
http://www.youtube.com/watch?v=EFLQ5PYKklo&feature=fvw