If we made you an offer, how soon would you be available to start?

Many healthcare facilities face a staffing crisis, so if that is the case for the Mayo Clinic, they are likely looking for someone who can start as soon as possible. It's industry standard to give a two-week notice to most employers, so if you plan to give your current employer the same, be honest about your availability to start. You could also offer to train on off-shifts if you have the flexibility to do so.