Instead of being random, which is very frustrating after finally getting to a temple, there should be a set code from the 1st to the last gate, which would remain in place for a week, 2 weeks, 3 weeks or a month (hold a vote )
EG: cat, dog, bug, face,O symbol, dragonfly, then next week something different.
If you manage to get through to the vault before....... let's say 10 attempts, the amount of treasure you find will increase for taking less than 10 "try's" to crack the code, and decrease after you have had more than 10 "try's"