Good to see you got it working. Here's where you went wrong originally.
<setattr [Boolean "Choice1Bad" _Boolean True]>
I'm assuming that "Choice1Bad" is the name of your scene behavior, and you have an attribute in that behavior named "Boolean". In that case, all you needed to do was change "Boolean" to "scenebhv".
1) The first argument in the list is always what type of resource the attribute is found in. Either game, scenebhv, actorbhv, actor, or dialog.
2) If you chose actor or actorbhv, you need to specify an actor name. The name is based on your use of the following snippet: GlobalActorID.set("Actor Name", _ActorAttribute);
3) If you chose scenebhv or actorbhv, you need to specify a behavior name.
4) And for all types, last is the attribute name and desired value.