I'm curious (because I want to do the same thing) how you arranged to get an interview without putting in your transfer application first.
I was fortunate to be able to scope out a new job at an RN open house! Had an interview with the HR rep, clinical coordinator and NM all on the same day. Once I expressed interest though, I had to fill out the request for transfer form and begin the transfer process (and inform my NM).
Actually, if I had been working in my current position one year (and/or not been a new grad) I could have gone through the transfer process without having to get a "release" from my job from the NM. The paperwork would have been completed and an offer given. Once accepted, then the NM would have been informed. But because I'm a new grad with less than one year at this position, things had to be done kind of backward, the other facility had to make sure I would be able to be released from my current job first.
Check the policy and procedure for intrasystem transfers at your system. More than likely if you have been at your current job for 6 months or more (and not a new grad) then you can interview for another position within the system, go through the transfer process, and get/receive an offer before having to inform the NM at your current job.
BTW . . just an update. .
I'm still waiting for a formal offer from the new facility! I did speak to the HR recruiter and there are a couple of details that still need to be ironed out as I transfer facilities. She explained that I will receive a formal offer but that it won't be made until all the "i's" are dotted and "t's" are crossed so to speak, regarding every detail of the transfer. So, I guess I have to wait a little longer to get an offer. I guess I could turn it down if I don't like it, but I'm not anticipating that . . considering that it's a straight day position with limited weekends and promise to pay more than I now make.