I think its entirely possible that Morgan went outside to acquire drugs of some sort, which is why there is such confusion as to how she accidentally got outside or why she missed the bathrooms. I think that her loved ones are probably trying to protect her reputation as most people would - Morgan wasn't a "bad girl" and they don't want to deter the investigation by making it seem that way. I know I would be hesitant if she was my friend to tell LE thats what she was doing - I might also lie as a college student and say she was trying to go to the restrooms, especially maybe if her friends that that would implicate them in some sort of drug use. I think she was intoxicated and thats why it didn't fully register that she wouldn't be allowed back inside or she wouldn't have probably taken the chance. I mean, she really wanted to see this concert. The ideal thing would have been for her friends to meet her at the gate and give her the keys but maybe they were less inclined because she was intoxicated and they worried about her driving off. At some point I think she tripped and fell because she was intoxicated. This happened to me once, I fell and hit my temple, I got up and I was extremely disoriented after the fact. This is probably why she was acting so out of character. The only reputable eyewitness account in my opinion is the guy who said she tried to get him to pretend to be with her, everyone else seems like they saw the other girl without the leggings. Its also entirely possible that she was being sarcastic with her friends about getting a ride home and wanted her to come bail her out, but maybe her friends were pissed - I mean, you drive all this way for a concert and your friend gets stuck outside the gate trying to (possibly) score drugs and then she wants you to come outside too and miss the concert that you spent money on? When you're drunk your priorities get screwy sometimes, maybe her friends were belligerent that because of her they'd potentially miss the concert. I think it may have been a sarcastic "yeah don't worry about me, I'll get my own ride home." After the concert it did seem like her friends waited around for her, maybe they were concerned and when they sobered up suddenly it didn't seem like it was the wisest thing to leave her out there on her own. I think her encounter with the one guy who she wanted to pretend to be with her indicates that she started to get troubled pretty soon after being stuck outside, maybe she was being harassed by some guys and wanted someone to seem to be her boyfriend. Maybe the guy she tried to score drugs from saw a pretty girl who was all alone and made some inappropriate comments. Its not farfetched for her to start feeling weird being by herself in a parking lot outside a concert - there are a lot of weird people that hang out there. It may seem farfetched to be assaulted twice in one night, but I've also thought that maybe she was assaulted within the arena parking lot, and the guy took her phone battery so she wouldn't call anyone and she dropped her purse. Maybe she was all disoriented afterwards and tried to walk away and got to the bridge - either the same guy came back because he started worrying about leaving her alive or she was picked up by someone else with ill will. I do think this was random and a crime of opportunity by someone who lived in the area.
