door question

Ok, I have something I can't figure out and it's driving me nuts.

Here's the scenario:

I have a set of stairs that I don't want to be used after a certain tag is switched on.

So I made doors 6 leading to 7 on the map. Then I made a door 9 off to the side, and linked it to 6. I made an "on-step" invisible npc to run a "use door (9)" script and put it over the door 7's tile (door 7 isn't linked to anything). This should have made it so you can travel between these two doors like normal.

This usedoor NPC is supposed to appear if tag 44 is off, so until you've done a certain thing you can use the stairs to go back and forth.

After a scene I have set up which turns on tag 44, another invisible npc which I placed on top of the door replaces the first and has a text box which runs a script moving you away from the door.

This part works fine. The first part, the door, does not.

Basically I have

tag 44=off : invisible npc running use door script over stair tile

scene with dialogue that turns 44=on

tag 44=on : invisible npc that runs "walk hero" script over stair tile

I've used this script before with no problems and I've gone over everything I can think of. Any ideas of something to look for that I could have missed? It doesn't make sense that the first script wouldn't work. Tag 44 must necessarily be off at that point because the second npc doesn't appear until I turn it on.

I'm not sure if I explained it too well so if I need to clarify let me know. And thanks for reading this and any advice!

I do believe you can just go into edit door links and set the door to work "if tag X is on." I don't think you need any NPCs or scripts for this.

I can't believe I never noticed those before. That fixed the problem, I just wish I could figure out what the heck was going on in the first place. Thanks!