I go to USC and I've been around CDU/MLK my entire life. I can't speak about after 12am (there is no reason you should be walking around at that time anywhere in LA without alot of people) but I've been there from 5 AM - 12 AM and never had any incidents or heard of anything. I probably felt safer there than walking around USC off campus at night. When the hospital was operating it was safer cause so many people were there and cops were as well (still see lots of cops hanging the campus around nowadays too). In terms of rotations, they'll be at St. Mary's, Harbor-UCLA or Olive. I've lived and worked around all of those and again, if you're not doing something you shouldn't be, you'll be perfectly fine. My father worked at St. Mary's and I used to consider transferring out of Manhattan Beach's public school system to go there instead. I would rather have my kids grow up in an area where he can learn to appreciate hard work and making his own accomplishments than be around wealthy, entitled children. And even if that's not how you feel, everything in LA is 20 mins away, so there's plenty of nice areas to raise your children. So in a nut shell, what you heard is vastly exaggerated. However, I did notice most people who have never seen an urban area before do experience an initial shock.