I don't know this hospital, but I generally grab several when I come on shift, put them in my pocket, and end up accidentally taking home a few often enough that I'd end up being able to have squirt gun fights with them.
Essentially, nurses go through so many that you'd be hard pressed to control them. We use them for everything from checking the status of an IV line to cleaning a wound.
I'm just amazed. It's frankly easier to use a flush than fooling with a sink. You need a flush anyway to administer the medication and I'd imagine most folks diverting IV meds are smuggling them out after transferring them into an empty flush in the first place. It almost makes me wonder if who did it isn't a nurse. Like a pharm tech doing a batch of them at a sink before loading the pyxis.