I think it is stupid not to have a plan B. Unless you have a 3.9 gpa, a 40 on your MCAT, your Dad is Chief of Medicine and you have been working in the health field since you were 6 then you aren't a shoe in to get accepted.
A plan B where you are doing something you really enjoy is probably best, also something you will want to leave should you get accepted the next time around. I wouldn't pick something based on the pay scale.
I didn't have a plan B when I didn't get accepted the first time around, I was so sure that I would get accepted..but didn't. Things ended up working out great though since I developed a plan B and worked for a year. It made me realize that I really, really wanted to go to med school. Now I am a MS2 in a program that I really like and I can appreciate being in school and learning instead of being out in the business world attending stupid meetings where nothing ever happens.
As far as the interview or application goes there is no shame in talking about a plan B. Med schools want well rounded people who will make good physicians. Having a plan B doesn't mean that you don't have desire, it means that you are a reasonable person. Desire is something that most people applying to med school have, it will not set you apart from other applicants.