What are some believable excuses to tell my parents for sneaking around the house at night?

I have a bathroom next to my bedroom, they probably wouldn't buy "I need water" or a toilet excuse. We don't have medicine downstairs (I'm sneaking downstairs). They are somewhat strict, but not terribly so. But I can't think of anything they would believe, I'm going on my "mission" at 1:20 tonight, please suggest something by then!
Asked May 02, 2016
Sorry this is late. But future advice, say you heard something and was seeing what it was.
Answered Jul 11, 2016

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