Excellent point. I wondered why she rented a car, too. You're right, it would greatly
She appears to have tested the waters and established at least a tenuous relationship. It appears that KB took the coffee without protest, so KK could be hopeful that if she offered KB a cup of coffee on a future date, KB would drink it without suspicion.
I agree with those who think that's just plain weird. There's no way I would eat or drink something brought to my door by a complete stranger. I wouldn't take something like that to introduce myself to a stranger. I wonder if KB asked KK which unit she was living in.
KK's casual attitude about having 'meds' bothers me - and I think more than anything, those statement have probably ended her nursing career. What reputable hospital would trust her now?
One other way dishonest nurses get patient drugs: at the patient's bedside. If a patient is on heavy meds delivered by a nurse, that patient may already be mentally distracted - too distracted to count the pills each time. Even if a patient challenged the nurse - "hey, I didn't get my little yellow pill", the nurse can tell the patient the doctor changed the med. If the patient brings it up to someone else, the nurse can claim s/he administered it and the patient's memory is unreliable.