I rewatched Star Trek Voyager S04E25, One:
After the rest of the crew is placed in suspended animation to protect them from dangerous radiation, the immune Seven, with only The Doctor for company, is placed in control of the ship [for 4 weeks].
It's such a good episode, when Seven, seeing no need for the company of others, finds loneliness taking a terrible toll on her. She hallucinates threats; her fears being embodied by crew members who appear to her in order to undermine her confidence.
"Seven, are you… frightened?"
"I am Borg."
- The Doctor and Seven of Nine