The move itself is kind of neat, however; what is the purpose? You can't just show the card like you did and then have it pop out from your spring. I mean...I guess you could but it is not very entertaining. I may being a bit too critical but you didn't even do a false shuffle and you can see the break line from the front quite easily.
I would have the spectator sign it, return it to the deck, go into a false shuffle or control it to where you need to and then do the move. Just my two cents.