When Harm and O'Neil get to the crated car they open the back and see the car inside. The way this car is packed in there there would be no way to get inside and back out. They would have to totally disassemble the crate and they had no tools to do so.
The gold chin strap for the combination cap for a midshipman should have a width of 3/8 inch, and that for a commissioned officer should have a width of 1/2 inch. However, the midshipmen in this episode appear to wear chin straps of the same width (1/2 inch) as those worn by the officers.