"If there's a door shut for him, he'll check elsewhere," said Avedissian. "He's constantly looking for other things. He wants to make more of a difference than anyone I know."
Clark attributes his progress to intense physical therapy and clinical studies, as well as to the stem cell therapy.
He describes his motor movement as more fluid and refined; he can now move his toes, stretch his calves and feel hot and cold on his legs.
Clark also lost the ability to sweat, which led to flaky skin and chronic acne. So he started experimenting with botanical extracts in his kitchen and developed the Clark's Botanicals skin-care line.
"The power of something as seemingly innocuous as beauty -- the power it has to make you feel strong and empowered -- there's something to be said about that," explains Clark.
He recalls being afraid of asking what he could do to walk, worrying that people would laugh at him.
"Now I'm not afraid of that, and it's evolving, because I'm feeling more and doing more," he says. "The people who I thought would laugh at me now look at me and say, 'Oh, my gosh, this recovery is incredible.'"
Clark hopes to empower other patients to take control of their recovery.
"Your injury doesn't define you. You will get better," he says when asked what he would say to those newly diagnosed with paralysis. "... You should want more and you should ask the questions that you really want to ask and then find the answers, and don't take anybody's word as truth. Use your curiosity and imagination to benefit your recovery."
Clark is seeking more cutting-edge SCI studies and continues to spread the word as a national ambassador for the Christopher and Dana Reeve Foundation.
He believes he is "definitely going to be walking" in the next five years and hopes to finally take a vacation. Most recently, he says, his feet began sweating, another sign of success.
But after his near-death experience, his priority is to just be happy.
Hearing that something is impossible "doesn't make sense to me anymore," he says. "I was three breaths away from dying ... It's about prioritizing what's important to you. My priority is being happy and feeling fulfilled. It's more about giving back to a bigger community with the experience that I have."