She was somehow expecting that he'd question her 'cause he would have been surprised when he didn't find her after arriving at the compound yesterday.
..She was expecting the questioning from him, but she wasn't expecting that it would happen today.
She wasn't expecting that he'd come to her house to ask the question, to know the reason why she suddenly disappeared yesterday. And this wasn't something she wanted them to discuss in the house.
She doesn't want any of the servants to hear, so they should talk about it outside, that was Lucia's plan.
Before the boy could say anything else, Lucia's voice resounded, "Let's talk about it outside".
"Why?". He inquired.
"No serious reason, let's just talk about it outside". Lucia's voice resounded again.
"Okay, if you say so".
The both of them stood up from the chairs they were sitting on and began walking out of the house. The boy came from his home to Lucia's home to question her, one question...that was how serious it was to him.