The best way I can think of is to have a server that you trust always running (it could probably be on an AWS or heroku server) but only you have access to, and you send all your personal siri traffic to it first (requires jailbreaking, but that's never been easier thanks to evasi0n). It could then fire off the door opening procedure via the already documented method. That way you don't need Sudoroom's server to be your primary siri proxy, as that could get pretty traffic intensive, especially if lots of people were using it that way.
I'd be happy to meet up say, Thursday evening to work on this with you, Wolfy.
Also just throwing it out there that there's a node version as well, albeit documented in Chinese (Fairly usable with google translate on):
Both of them are terribly simple to use, so it could just be a writer's preference thing.