Here you have to consider the numbers on the candles as three rows. So the top row reads:
1 2 3 4 6
Then it reads:
4 5 6 7 8
And finally:
6 5 6 9 4
So in order to find the missing numbers you have the complete the three series. The number in the top series will be:
1 2 3 4 6 8
Next the number will be:
4 5 6 7 8 9
And finally, the number will be:
6 5 6 9 4 1
Once you input the correct numbers, a key will be revealed. Use it to unlock the door and escape.