The Quickest Way to Lose a Million Dollars

I have it on good authority that, over this coming week (spring break), the entire UMASS Dartmouth campus will have new locks installed in every dormitory on campus. My source says someone at the housing office lost the master key that can literally open any residential door on campus, thus necessitating the replacements. The total costs of those replacements amounts to upwards of a million dollars or more, though the school could very well be insured.

My question: why even have a single key that can open any door on campus? Every building has a Master Key and floor keys. The housing office could keep a key to each building too (and likely does). Anyone can lose a key, so having one worth a million dollars seems a bit risky was clearly a terrible idea.