If you’re talking about someone holding an iPhone to someone’s face, there’s a setting called “attention aware” that verifies your eyes are open and looking at the phone.
> Attention awareness does not stop alarms, and it requires your eyes to be open and looking at the phone.
Attention awareness silences/drasticly reduces the volume of alarms, that's how it is designed.
If they have a bug in the attention awareness feature it stands to reason that it could not require your eyes to be open or looking at the device in question at the time.
https://www.bbc.com/news/articles/c0kl4glp547o (bbc news article about it)