It's not what you say, it's how you say it.
Trust me, they could care less where you'll be in 5 years. No residency can hire every graduating third year resident after they graduate. In fact, many of them want fresh "meat" from other institutions with new ideas, so as not to become too inbred. They want to know if you have a plan and are goal directed. Likely they don't care what your plan is, as long as it sounds mature, well planned, motivated, and that you have one. If your plan is, "Don't know, prolly will just take a part time gig somewhere, so I have max time to chill, get lit, and go where the wind blows me," they're not going to like it, even if "that's you."
Make a list of the 20 most likely questions, and either have someone "mock interview" you or mock interview yourself. Record your answers on your phone and listen back to them. Do this over and over again until you like what you hear.
I can't tell you how much this technique helps. "Just be yourself" is the worst interview advice ever. Be your best, groomed, well prepared and polished self.
Rehearse these questions.
It's easy.
IT'S THE SAME DAMN 20 QUESTIONS EVERY PLACE, EVERY YEAR
Prepare, and you'll kill it.