Player in-game notifications

I want to create a way for someone in the real world to notify me while I'm in a VR app that they want my attention. My husband has tried tapping me, but it scares the SH*T out of me. He's also tried to shout to me, but I'm usually playing Beat Saber at a high volume, so I don't hear him. I have experience in C#, C++, Java and Unity. I envision a non-VR PC or Android app that would send some signal or message into my current VR space, whatever it may be. I'm assuming it would have to be done though the Oculus Platform SDK to access my account, but the sender shouldn't have to have an Oculus Home account. I'm assuming that Oculus/Facebook is still working hard to flesh out the balance between the privacy/security/social aspects of VR, so this probably isn't possible yet. Does anyone here know of any current technology that would allow this - or do I just have to wait? I'm sure there are others who would want this.

Hmmm... as I re-read this... I'm thinking... the message doesn't have to be visual. Maybe I could write a network listener that can tap into the Rift Audio device and play a non-jarring audio clip to it - starting quietly and slowly increasing in volume? The outside person can trigger the listener by sending some TCP/IP data to the listener program. Any thoughts?