This play is a good defense for a walk-off from first. The key to the play is getting the ball to the second baseman before the runner gets past him.
Once the walk-off has occurred and everyone yells walk-off, the pitcher steps off the mound, freezes the runner at third and quickly throws the ball to the second baseman. The second baseman must judge the speed at which the baserunner is moving and take an angle so he can catch the ball a few feet in front of the runner and in the base path. The baserunner will not expect the ball to be thrown to the second baseman and it can result in a quick throw and tag play for the defense.
If the second baseman cannot get in front of the runner the pitcher must recognize this and get the ball to the shortstop who will be covering second base by this time.
(Currently the flash videos are only working in Internet Explorer, I will be working on upgrading them to work in all browsers. Sorry for the inconvience.)