First of all, I'm not a fan of people who say the actions of characters in movies are stupid or illogical, or that no one would actually behave in that way, because usually they are talking about a situation that they have never personally been in, and more importantly, all people react differently to situations so who are we to say how the characters should react.
That said, these characters' actions are too absurd to be believed, and the only reason for such behavior is to further a silly plot. For example, the women held captive is going to bop the captor on the head (who is holding her hostage with a gun) and knock him out several times throughout the first 30 minutes of the movie, at which point she could easily grab the gun and be in control, but for some reason she repeatedly tries to run, at which point the captor magically awakens and catches her again, only to be hit and knocked out again, and so on and so forth.
Furthermore, it becomes clear right away that the captor knows she is concealing her identity by repeatedly asking her name and getting angry when she answers, "Cathy." So everyone knows she is not actually Cathy... but Cathy fails to realize this and is flabbergasted that he keeps asking who she is. She was arguably the most frustrating and annoying character to listen to, but one also has to wonder why Luke Evans does not just stop asking her name and reveal that he knows exactly who she is. It's stupidity of both characters in order to try to build suspense/mystery that really ends up being irritating.
On top of all that, the ending is quite unsatisfying. If you thought all this nonsense was building up to some awesome twist or revelation, you'd be wrong.