It depends on your job in the USAF. I was a security augmentee[0] and we did not chamber a round. But the Airman who died likely protected missile silos, which are "no-lone zones" and they would be carrying with a round in the chamber.

https://en.wikipedia.org/wiki/Two-person_rule

The P320 is known to have accidental discharges for civilian owners (honestly - don't buy one). But Sig Sauer has stated that the M18 military version did not have those problems. We will need to wait on the results of the investigation to find out.

[0] An extra duty typically assigned to junior enlisted - we only armed up during exercises. Which brings back a story - we were waiting on the trucks to take us to our posts, and the room was full of Airmen armed with M16s and M60 machine guns. And we were all watching Justin Wilson cooking up some delicious Cajun food on the TV.