She will be sent into a washroom with no sink, and a toilet with Saraann wrap on it.
So substitution is easy. She has two choices synthetic or real but clean.
So, should she keep this powdered piss on her person so they don't check her pockets? (I know it must be mixed with water and up to temps) I assume no purses?
Also, what should she do with the Saraann wrap? Remove it? Ask WTF is with the wrap? Leave it and if they ask tell them you emptied your tank in the cup?