If all else fails, the next time you are interrupted simply say, “You have some great questions and I want to make sure I respect and answer each of them. So why don’t you see me afterwards and I’ll give you some more in-depth answers. Now let’s move on and keep the flow going.” Most likely they will not come to you afterwards because their whole goal of interrupting was to shift attention from you to them.
Check out the HOT Tip Clueless Questioner for another example on how to handle someone who interrupts.