To find the hidden treasure and rescue the princess, you must cross into the deep chasm. The way in is often not the way out. When you find the hidden droid, the tractor beam will have been disabled by Old Ben so you can get what you came for and escape the evil empire.
As you ready for your leap, this would be where Leia first gives Luke a good luck kiss. Good Luck with that! You can accept the kiss before you go, but you have to leave the stamp where you found it. The ongoing mission depends on the stamp being there.
Be on the lookout for Darth Vader lurking nearby, for your destiny lies along a different path...