There are only a few words you can say to the people you credit with your life.

"Thank you, thank you, thank you," Sandy Boyer,67, said as she hugged her ER nurse on the night of October 2, 2013.

Boyer, overwhelmed with emotion, searched for the medical staff who took care of her and her husband, Marvin, 74. He was told he wouldn't survive, but is up walking around.

The Boyers are two of 12 survivors of the I-40 church bus crash that killed eight others. The Front Street Baptist Church bus, driving from a retreat in Gatlinburg to Statesville, North Carolina, blew a tire, crossed the center median, and hit a semi truck head on.

Thursday, the group of seniors met with UT Medical Center's team for the first time since they left the hospital. There was no shortage of hugs, smiles, and tears from both the survivors and staff.

All this week, the congregation is on a mission trip in Jefferson County as a way to serve the people who helped them in the time of crisis.

MORE: Bus crash survivors return to East TN to say thanks, serve others

"These are family. I made them my family. That's why I came [to Tennessee]," said Sandy.

"To see him [Marvin] up and walking is amazing. I was expecting him to be in a wheelchair so to see him up and moving is amazing," said physical therapist, Emiliy Fico.

It has taken months for the seniors to heal. Many are still recovering. But nine months later, they wanted to shake the hands of the people who helped them get to this point.

RELATED: Inside the ER on the day of the church bus crash

"I lost my memory when I get in the wreck, except what people have told me," said survivor Benny Eldridge. "But the care they gave us, the things they done for us, makes all the difference in the world. It's great to know that there's people that do care."

For some it's like they are meeting the staff for the first time. But others couldn't forget the people who cared for them in the weeks they spent here.

"She was so patient and kept working with me," said survivor Libby Elledge as she hugged a nurse. "They were always so wonderful to us. Everybody was."

"You made it easy because you were so sweet," said her nurse.

They also know it's not just the people in this hospital who prayed and cared for them.

"We stopped at a quick pick market today. And a young man said, 'Let me shake your hand,' I want you to know I was praying for you," said Sandy Boyer, "Everyday we find someone new."

RELATED: Young at Heart group shares story of "miracle" survivor

Their mission trip continues through this weekend.

The church also plans to host appreciation meals for the first responders and law enforcement.