The merchants hang onto the quest items, so you can buy them back.
If you toss the grail repeatedly until you get to the door, then pick it up and leave right away, you can avoid greyface and the other mummies. If you wish, you can return when you are stronger.
IMO there are not enough traps in the game that do enough damage to justify the Evade Traps skill. I'd rather buy Spell Shield and Aura of Guarding spell books, or rely on better armour or
restoration potions.