Coulter somehow maintained his anger and instructed Lydia in a requesting tone. It was the utmost wise thing he could do acknowledging that his daughter was no less than a chaos. She could as far as her abilities allow her, just to ruin his mental peace so she could gain some moments of attention from him.
"Okay, okay. I am coming back home right now, but promise me you would not do anything reckless. And you will behave till I come back."
He instructed her politely assuming that she will obey, mating with someone was not a child's play. It meant that Coulter was now unable to break her bind with that guy. And the particular thought that he could not simply trust his daughter scared him to the core.