I don't think that we want to use the left door, but I think the combo is "TAD9". It could also be "TAD3" or "TAD4", but I think those numbers might be somewhere in the riddle.
Also, in regards to the forward direction, I think the indentation plays a key part. The indentation seems to go:
00001123021
Hey @iiiidk, when you look at the right door, is that message in the top right supposed to be "50" or "SO" or some combination of that? Or are we not supposed to know