Frank who had already left the restuarant was already aware of her forced departure from the restuarant as well as the culprit as well.
Thinking back, he already had an idea of what Walker had planned the moment he walked into the restuarant.
That on its own only meant one thing.
Alicia wants to meat 'that person' again. She willingly had herself kidnapped just to reach that objective.
...
FLASHBACK
Five years ago when Frank came to know about Alicia's existence he was at first taken aback and was not sure how to handle the situation. 'He had a niece now' But where did she come from?
Why didn't he know about her before, what happened to the kid this whole time?
Most importantly who is she? ...
When Frank tried to reach out to his brother Felix, he was even more frustrated. The man was the most stubborn about the kids existence. It was as if he hated her existence all together.