If you have some programming skills...
ftp://ftp.idsoftware.com/idstuff/source/quake2.zip
That's the quake2 source code. Id released it today! Rejoice! :D
Scenario designing and game designing are nothing alike ;).
Game designing is so vast...scenario designers are more like artists than programmers imho;)
And btw, what does Quake 2 modding has to do with SWGB scn editing ?