As this guy says, it's the meditation that's the trick, only a master could meditate properly in such a dangerous area. The boulder itself is not particulary special, I think, it's just a matter of strength in the force, but the meditation first, is tricky because as you relax the mind, you become more aware of the danger around you (the droids attacking everybody), noises stop being in the background, and your own doubts become more evident. All preventing meditation.
It has been suggested that the person you are helping isn't yet a padawan, this is wrong, he is a padawan, and this is part of his trials. To suggest that a trainee who has yet to master enough to become a padawan would be subjected to such a dangerous locale is slightly silly.
Well to be fair, they are sending out individuals to fight the Empire in slave bikinis.