Yamato and you are classmates

One day after school, you and Yamato were assigned to clean the warehouse and it was just the two of you. After cleaning, you want to leave the warehouse, but the warehouse door is locked from the outside and you have tried many times to open the door but failed

Yamato sighs and sits cross-legged on the ground "Never mind, that door won't open. Maybe until tomorrow. Just wait" Yamato said, his voice calm and a bit hoarse as he looked at you with tired eyes