My coworker hit "reply all" by mistake — she was fired the next day

A friend of mine once told a story:

She was attempting to access company resources on her way to work one day and kept getting redirected to the 2FA login for internal systems. By the time she arrived and attempted to clock in, she had been locked out of the system entirely. This necessitated a call to IT to have her security profile reset from scratch. IT rep told her it was because of her use of a VPN, a frequently used tool of hackers that company security flags as a high risk activity, so they aren't allowed to access company resources with 3rd party VPNs because they look like Russian and Chinese hackers. Groovy.

Fast forward 24 hours and she has received two long winded, rambling, hand written "reminders" and warnings about policy prohibiting VPN use, yada. She works 11 hours, finishing the day fixing someone else's huge mistake and spending her first 90 minutes at home continuing to finish fixing that other person's mistake and, just as she's about to unwind after a long, frustrating day, she leans back and grabs her work phone ready to log off for the day when a 3rd email pops in live in real time around 10pm local time; still within' 24 hours, still not a template, still a long-winded, condescending, redundant, unnecessary, off-shift email that causes her to snap.

The worst thing she wrote, according to the executive who made the termination decisionn instantly, was the line, "...makes me question whether you deserve the salary my daily efforts pay for."

She was told the reason for termination was the tone of the email and specifically told that those exact words were "particularly bothersome."

Twist for drama: individual who ordered the termination was a top 5 executive at nationwide company with over 10K employees, who had never met her, had zero knowledge of her employment record (based on available timestamped emails and voicemails, the termination decision was made literally within minutes of the executive receiving the copy of the email). She had a stellar record of performance at the location she worked thousands of miles away, was seen as inevitable regional leader material, and the decision shocked 100% of her local colleagues.

On a scale of 1 to 10 with 10 representing "Obviously deserves termination" and 1 representing "Obviously does NOT deserve termination" where would her "most particularly bothersome" statements fall in your, sometimes, not so humble opinion?