Here is the thing we need to remember; no matter what the circumstance Elizabeth was kidnapped by Cummins.
Cummins manipulated her. He is a criminal.
There are all kinds of scenarios we can consider.
*He took her against her will and threatened her to the point he felt he could take Elizabeth out in public and not worry about her running off. Deeply scared her with threats.
*He took her against her will and brainwashed Elizabeth into thinking she is doing the right thing by staying with him.
*Elizabeth left with Cummings willingly
If Elizabeth left with Cummins willingly so what? He is a criminal and a creep by manipulating her. 15 years old is not considered old enough to decide you can run off with someone.
Cummins knows he is a criminal.
My point is Elizabeth is a victim of this creepy old man (old to her anyway), and he will be charged with, at the very least I would think, kidnapping in the 1st degree no matter what the scenario.