If we're talking about the same play it was the last few minutes of the game. You don't punt down by multiple scores late in the 4th, you go for it. You're not going to win, but punting makes zero sense in the context of even pretending to try to win the game. Hence it would make at least some sense for Kamara to go out of bounds in that situation. Not a lot, but some. The point is there's a plausible reason other than cowardice.