What a week

On Monday I was promoted to senior and on Friday the other senior in my group was fired for gross incompetence.

FEELS GOOD MAN

New here, don't know the format, etc

Let me describe my Friday:
8:45 standup
By 9:30 I'm done following up with 3rd party platform vendor's jira, and curiously look into an issue related to app camera not working in development build (we aren't in production), fix it in 5 minutes and talk to the team of two other devs. Tell them I've submitted a fix, and QA is unblocked.

"Senior" software dev starts complaining about how "I've wasted my whole morning" because "I mean, come on" and is generally offended because "I've done their work."

After a real puzzling argument, I worked from home the rest of the day.

Where did I go wrong?