How did I get a Slack notification while in UEFI Settings?

Question

Windows 10, Ryzen 5 1400 PC. I had shut down Slack to avoid distractions, and then got a notification that it was time for a reboot for Windows updates. After I was done with the task at hand, I rebooted the PC. During bootup I tapped DEL to get into the UEFI settings. While I was browsing the UEFI settings, a Slack notification played through my computer speakers. I was perplexed but thought it must have been my phone. A second later, I got a notification on my phone, and that's when I remembered that my PC and Phone Slack apps have different sounds."OK, maybe somehow W10 has booted while I'm sitting here in UEFI" so I exited UEFI settings, booted into W10, and... Slack isn't running.I have to admit that if it didn't happen to me, I'd never believe a person who told me this story. But I can assure you it's true and I'm sure of the circumstances I've described.So how on earth did I get a slack notification from my computer after I had shut Slack down and was in the middle of a reboot?

TowerTall · Accepted Answer

Why you think your phone is vibrating when it is not https://www.bbc.com/future/article/20130701-why-you-feel-pha...

geocrasher · Answer

FIGURED IT OUT. For all of the three people following this:
My speakers are arranged so that I don't hear them directly. They point at the wall behind me, and I guess I mostly hear them off that. Also behind me on a desk, where I did not remember leaving it on, is my laptop which also has Slack running. As a result the sound was coming from behind me which sounds exactly like my speakers.
I
Am
An
Idiot

mod · Answer

I can't solve your mystery, but your PC didn't get a slack notification while you hadn't yet booted the OS.It's something else. That's too big of a conspiracy to be the answer.

ja27 · Answer

It wasn't one of their annoying ass tv commercials?