For those who were fired, infosec ran a script during the CEO call to pull their access packages for production systems, crank the data-loss protection systems on their laptops up to high, boot them from Slack, and prevent them from sending & receiving emails to non-HR folks. After their "fired" email they received an invite to talk with HR to provide updated contact information. Then infosec pushed a new password to their account & force shutdown their workstation.
If it sounds brutal, it was. But the layoffs I was involved at a previous company were handled much differently, more traditionally: CEO announcement at 9am, and then you spent the rest of the day agonizing and waiting if you're going to get a :15 private calendar invite from your manager titled "Employment", or if you'd make it to the end of the day with no news (good news!). I'd almost argue that moving fast was more merciful than this, but that's easy for me because I wasn't fired either time.