I carry 60 ft of 3/8" nylon rope and gloves on my BOB. If I were a student, I would throw it into the bottom of my book bag, and get both instruction and practice at rappeling.

Rappeling down cliffs have expedited my movement more than once. That, and to haul equipment up (mostly the sides of locks) is why I carry the line and the leather gloves.
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QMC, USCG (Ret)
The best luck is what you make yourself!