The way I saw the pick unfold was that Indy was unstoppable on that drive and looked like 7 was a sure thing. The Saints could see this and were just hoping that they could get the ball back drive the length of the field, kill the clock and kick a game winning field goal with no time left.. It was an almost let them score quick kind of thinking to get the ball back. So I’m sure the D had a green light and Tracy Porter bit on a route he has seen all freaking night knowing if he got burned it was not the end of the world and it worked out for him and the Saints.
The 2 point convert was a give in with them making it and going up 7 or miss it and go up 5. 6 points means f all knowing that if Indy was to score being up one or two still means a field goal wins you the game. Going up 7 turns it into a 2 score game to win.