That's my theroy

It's possible that she has no idea what happened to her.

If she does "bust" Regina, I'm not sure it'll be in the way we're thinking. Regina's going to have some way to get out of it like she did with the playground. She has to stay in power in order to control things. I doubt she can control them (as Mayor) from a jail cell.
I do think bri-marie might be right though. What would be a better way for Regina to stay out of handcuffs, right?

Regina's too witty in her evilness... I'm sure she has a backup plan.

But they would or shoul question her and their would be a witness agianst Regina or worst mr. Gold

Not if the time between her driving and her showing up in the alley is all a big blank.

Regina always gets out of everything so I don't this will be any different. I'm guessing Kathryn won't remember what happened and since she's alive the case will likely be dismissed. But atleast Mary Margaret will finally get out of jail.

I honestly don't think she was responsible for her disappearance. I think Mr. Gold was. How else did she turn up suddenly, Regina certainly wouldn't let that happen if she had been the one who "made her disappear".

I think mr. Gold did it.

That's my thery too that mr. Gold did it but I'm not sooo sure

Nope. Regina always has a plan.