Jeremy,
Thank you for your question! It wouldn't be a Script Control that would "stop" the playlist, but instead a Sound Control. This Sound Control needs to be setup to "Stop All Sounds". It also cannot be directly above or below a Script Control/Sound Control (if so, insert a Blank Cue in between these and have it Auto Advance at 0 seconds). Also, please make sure that you also have a cue AFTER the Sound Control so it has something to advance into. Again, this could be a Blank cue set to Advance at 0 seconds.
If this isn't working for you, or if you need assistance with this, please give our Support Team a call. 866.857.1292
Thanks and God Bless,
Ryan Zeeck