Bear with me, but could it be possible MT became pregnant, panicked, and went off with someone who was going to help her deal with it? Many college kids have several fake ids so they can underage drink; and a trip to planned parenthood somewhere she wouldn't be known would be an easy way to get the care she needed with no questions asked. With the wedding trip coming up, she may have freaked out that someone would realize she was pregnant (morning sickness?) and thought this would be a 24 hour experience, but then had complications. Could have ended up in a hospital as a Jane Doe uninsured getting care... With the way this case then blew up nationally in 24-48 hours, the kids (MT & friend helping) may have been scared on what to do next... And overwhelmed... what do we do now...maybe DJ wasn't the father and something happened at school toward end of freshman year...
Just pure speculation; but it would be hopeful to think she is alive and will return...