They were being followed, Arianna found out. However, she was calm knowing that it was Marcel's people trying to make sure that they were safe.
Honestly, Arianna was touched by the gesture. Had it been in the past, she would have thought that Marcel was simply following her to secure his prisoner and make sure she doesn't escape him.
And that brought her back to the question, will she escape him though? It was no longer a question of "Could she escape him?" because Arianna was sure to have found the way already. Marcel trusted her and that was powerful enough for her.
However, it was now a question of decision, 'will' she escape him? And of course, it was complicated as well. Maybe she would, but that would be in the future - if he gave her a reason to run from him - for now, she would spend time with him and explore these raw feelings blossoming between the both of them.