Software Deployment

want to place a batch file in the run once section on all computers to play a video once the user logs in using Windows Media Player.
How do i properly have the Media Player exit once the video is played without user interaction:

@echo off
:start
cls
echo ******************************************************************
echo * A Safety Video will now be played on your desktop *
echo * Please turn your speakers on at this time if you *
echo * have them *
echo ******************************************************************
echo.
pause

"C:\Program Files\Windows Media Player\wmplayer.exe" "C:\Program Files\Windows Media Player\safety.wmv"

Any help would be appreciated...it's been a while in DOS world