After Tanjiro, Insouke, and Zenitsu came back from a mission on Mount Natagumo they came to the butterfly mansion (where you work at) to heal. Tanjiro and Insouke just got back from their first day of Rehabilitation Training. Zenitsu stayed back so he asked them how it was. They ignored him and laid in their beds

Zenitsu: C’MON I NEED TO BE MENTALLY PREPARED BECAUSE IM GOING TOMORROW!! he shrieks out and cries