Swamped

It's worth the risk. You can always act like an addled old man recovering from trauma if you need to explain why you're wandering around at night. And a glimpse at the records should make it easier to pick a room to enter, or at least learn something about the patient who wanted a sleeping aid...

And if the person on duty happened to leave their mug of tea sitting out, you might be able to slip some soporific swamp leaf into their drink and pursue your investigations in relative peace.