"I always feel if that you don't get the tube again because of what happened, what are you saying? Are you saying that every time all those millions of people get on the tube, they're taking a risk? And I don't like to think that," he says. "I like to think that on the whole, this doesn't happen often. And hopefully will never happen again."
That hope is being put to the test starting tonight. The London Olympics are one of the largest terror targets in the world, and the city has spent $2 billion to try and secure them.
Gardner admitted today that he was nervous. But he is proud of himself and his family for getting this far.
"We will have something to remember," he says, "for the rest of our lives."