The way i did the quest was to be with a friend and we must have traded water and food so many times so we both survived. Even so i had to take two trips back to al kharid for bank runs. I didnt know of any places in the pyramid that you dont get attacked and can heal yourself other than the bit just before the jump. (middle of picture) So when i got through the hidden trapdoor corridor (along the bottom of the picture) i jut ran til i got to the bit before the jump. Even when you waiting to heal you have to take drinks of water though :(. Lastly always wait for your energy to get back high before attempting the jump or you will fall. Evn then i fell down that hole quite a bit. Other than that good luck with it. :)