Pacquiao, has the following to say on killer instinct:
One thing about fighters, we have to have a killer instinct. If we
hurt somebody we know to go for the kill. For the wolf it's live or die,
and for us in the ring it's live or die.
This quote is excerpted from the documentary "The DNA of GSP", which is expected to come out in October 2013, and is directed by Kristian Manchester and Peter Svatek