Control your emotions doesn't mean we have to avoid your emotions. In the process of controlling emotions, people get consumed by them and that is what happened with Leah. She was grieving with guilt for the one mistake which was putting her family life at stake.
But when Leena appeared looking for her, a sense of security loomed in her. She was fretting out of pain since morning with the one phone call from that person. But right now she is not scared when she saw her friend. Leena has appeared like a star in her darker situation.
"I am sorry for yelling at you," Leah whispered. Her guilt blew up when she reflected on her thoughts. She had blasted at Leena for looking secretly into the phone when she was only trying to help her.