In the brief window of lucidity that the night nurse's lateness has provided you, several options stand out in your mind.
You could try to overpower the nurse physically, though the thought makes you ill. You are bigger and stronger than she is, and your calm behavior to this point has allowed her to become comfortable in your presence. She even sticks her finger in your mouth to help check whether or not you've tucked your pills into your cheek instead of swallowing them. She wouldn't expect violence.
You could try to manipulate the night nurce socially, convincing her you are ill or injured and need to be treated. She is unlikley to listen to your words, you're schizophrenic after all, but hard evidence like blood or vomit would be very convincing. In the confusion- she's likley to summon help quickly- you may be able to slip out or at least try to palm her keys.
Time is running out, and you need a plan of action, now.