Hi PhilShifty11. Do you have the Rattle and Plasma Caterpillar artefacts with you? The Miner told you to bring these, and if you aren't carrying them the Shadow Monolith won't talk to you.
When you entered the glitched door, I assume that you couldn't get past the coded door mid-way up. This is the door code that the SM gives you. The safe is in a room on the other side. The codes for the top and bottom exit doors were on the casket that you found earlier, and should be recorded in your diary.
If you can't get the SM to talk to you even with the Rattle and Plasma Caterpillar, the code that you need is
(The other door codes are
Don't forget to pick up the items that Sidorovich wants.