University of Florida student Melvin Thomas tells PEOPLE about the semester the Denver Broncos QB was just another one of his classmates

As far as college classes go, Melvin Thomas wasn’t looking forward to biology lab. The University of Florida student would rather take a humanities course or an economics course or something more reading-intensive. Science, not so much.

But his biology lab would prove to be one of the more memorable courses of his college career.

Get push notifications with news, features and more.

His appreciation for his weekly lab started on the first day of class: the day Denver Broncos quarterback Tim Tebow walked into the room, nodded in his direction and sat down in the empty chair at his desk.

“Hi, I’m Melvin.”

“Hi,” Tebow, then the quarterback for the Florida Gators, replied. “I’m Tim.”

They exchanged phone numbers.

An Unassuming Presence

“It was surprising,” Thomas tells PEOPLE of the moment Tebow – whose six-week winning streak came to an end Sunday night in a game against the New England Patriots – walked into his class, prompting the room to fall into a hush of college students “playing it cool.” He adds: “He honestly didn’t assume anything.”

It was January 2009, and the UF athlete superstar had just returned to Gainesville, Fla., in glory from a victory BCS National Championship game in Miami. He had already announced he would spend his senior year as a Gator instead of entering the NFL Draft. He was recovering from shoulder surgery.

Thomas says the two worked together nearly every week on assignments for the lab, which was geared toward non-science majors. (Tebow graduated from UF in December 2009 with a degree in family, youth and community sciences.)

When the class was working on a lesson about evolution, Thomas says Tebow “never argued or generated conflict” about the course material. “He did whatever he had to do for school,” he says.

Thomas says Tebow, an evangelical Christian, believes in microevolution (as opposed to macroevolution, which refers to large-scale evolutionary changes).

"The Busiest Person"

As far as star-sightings go in north-central Florida, he was “as much as a celebrity as any student could ever be.” Even in a charming college town with a population just less than 125,000, Tebow and Thomas had to plan their study locales wisely.

So the library was off-limits.

The two would often work in Thomas’s dorm room. Study breaks meant playing NCAA Football on Thomas’s Xbox.

“He was really chill – down to earth,” Thomas says. “He’s probably the busiest person I have ever met in my life at all times – aways doing something.”

“Doing something” often meant doing good for Tebow, who was no stranger to charity work even in college. (His Tim Tebow Foundation is now helping build a children’s hospital in the Philippines.)

But sometimes doing good meant making a fan smile.

Thomas remembers going to the Florida Museum of Natural History on campus with Tebow to complete a lab assignment. They filed through the museum, filling out a worksheet about the evolution of stingrays and various creatures. There was a class of local students there, too, on a field trip.

“Half the time Tim had to hide because if a bus full of kids saw him, we’d never get our assignments done,” he says.