Q: If I have two Goals which I must play,* one of which makes my opponent win, can I play both at once with the one that makes them win buried, to prevent their win?

* Either due to Draw 2 and Use ‘Em, or having a Play Rule higher than the number of cards in your hand.

A: No. Any time a Goal is played, it provides a chance for someone to win with those conditions. No matter how briefly that Goal is in play, it counts, and if someone meets the conditions in that instant, they win.