The other day I lost my keys on campus, so called the campus police to come open my car for me. They were there within a few minutes, though it took the technician awhile to work on the door....finally he called for some back-up who had each side of the car open in 30 seconds. I was grateful for the help, even though I still couldn't find my keys after I got in. At least I was able to sit in my car to wait for a spare to arrive instead of standing in the cold for 45 minutes.
In general, I've never felt threatened on campus, but there are blue light posts with emergency phones to call them. They'll help you get into your car, or if you feel unsafe they'll escort you to your car.