/vr/ - Retro Games

Okay, let's say I want to make a mechanism akin to Zelda's floor plates, how would I do that? Is there any means in (GZ)Doom Builder for doing it on UDMF?
Want I want to do is the following:

When I step on this floorplate, a door should open and AS SOON as I step off the floorplate, the door shall close, so that I can't reach it without any other action that keeps the door open.
The door is in view, so behind it on the wall there will be a structure that is to shoot in order to keep the door open.

What I am currently struggling with is that floorplate. My current system goes like this:
I have a sector with all the outer linedefs opening the door when crossing from the front.
Then I have right around it a set of linedefs closing the door when crossing it.
When going slow, it works well. Step into sector, open door, step out, close door.
The problem now is that when I start above the sector and just run over it, only the door open action gets triggered because the door close action is too delayed (?). This means I would need some kind of positional tracking which says "While I stand in this sector the door is open, otherwise it is closed".

Next problem is the switch keeping the door open on the other side. My idea was to simply change the tag of the door so it won't be affected by the open/close actions anymore. However, I couldn't find anything to change that tag. I also couldn't find any function that lets me e.g. remove the tags from the linedefs, so I have no idea how to keep that door open.

Will I have to use a script for that? If so, are there any good scripting tutorials?