2 years ago, it would have been easier because Amazon allowed users to have their own music library that they can upload themselves. Amazon removed it so it's no longer an option. If it was still available, you could just upload a mp3 file with a quick door slam sound and have Alexa play the sound in the routine. There are some other ways for Alexa to play from your own music library such as Plex server. I'm not familiar with Plex or other alternative sources. I'm sure someone else can chime in on that.