Was told by a coworker that our supervisor accidentally let it slip that someone in our department is getting fired/replaced, there is only me and said coworker in our department.

What should I do. I’ve been working there for almost 4 years. I’m 20, it’s one of two jobs on my resume I’d hate to get fired from it. Me and said coworker are both worried and confused as we are both meeting our jobs standards… advice would be greatly appreciated. It almost feels wrong for them to just fire one of us like that and out of no where with no warning. Edit: forgot to add they apparently interviewed and hired the replacement today