I'm not sure what the actual scripts are but I know a way you can find out. look for the "night of the mantis" map in the content browser. it has the exact concept you're looking for and you should be able to look at the scripts on the terminals there and copy them down.
N.O.M. is way too complicated for a novice scripter to emulate.
This is very simple to do. Place a brain and make it the Defender teamside; it will turn red. Add a script to it. The script will be score check, and set it to whatever score you want the event to trigger under. The action will be message send (alpha? use whatever unused channel is open). Duplicate this brain and change only the teamside; make the duplicate an attacker brain (this will allow the door to activate after the score is reached by either team). On your door, your scripting should be message received alpha?, action 1 move offset however much it needs to move.
If your gamemode will have multiple rounds, add a second script to the doors, round start, action 1 position reset; this will help ensure it's closed at the start of a new round or a scenario where the round ends early while the door is still open.
Good luck, Spartan. I can help you out with the reducing score portion, after hitting a button, but I don't know what you're doing with this mechanic or if it's even worth the frustration to you. Let me know if you absolutely need that mechanic, because some of these scripting suggestions would need to change. It's the weapon points system, so it probably doesn't need to be applied to your doors.