Ethos is not a personality trait; it is produced by specific sentences you choose to say. And fear moves people only when it arrives with a way out. This closing opens the way most student closings actually open — asserted credibility, the worst case you could find, plenty of threat and no exit. Repair it, and watch whether the room ends up managing the danger or just managing the fear.
1 · Ethos, sentence by sentence
Competence
Trustworthiness
Goodwill — eunoia
2 · Emotion, and the fear-appeal rule
The story you tell
The four sentences — two about the threat, two about the response