Cosmo,
Would you kindly test this for me? --> VarsTest
It is a simple test program with a this.XXX_VAR in a script, room, and copy.
Just to see what access results come from where.
My console log reports the following showing that copy does not read the room or script variable, and room does not read the script variable.
from script1 -> script1 value -> 123
from copy1 -> room1 value -> undefined
from copy1 -> script1 value -> undefined
from room1 -> room1 value -> TestValue
from room1 -> script1 value -> undefined