Thornton absorbed just enough contact from Hagins that he back-rimmed the dunk, which detracted little from the play, the attempt and, most important, the potential of the most physically gifted player in coach Tony Shaver's tenure.
"Unlimited," Shaver replied when asked about Thornton's upside. "He has a lot of room to grow in this game, and we will adjust our program a little bit — we always do, based on the talent and individual skills of a kid like Brandon Britt or Marcus at their positions — but I think there's a really high ceiling for him."
Thornton's education continues Saturday when the Tribe (4-18, 2-8 CAA) faces conference title contender Old Dominion at the Constant Center (4 p.m.).
Expect the Monarchs (13-9, 8-2 CAA) to shade toward leading scorer and 3-point threat Quinn McDowell, but also to keep an eye on Thornton, who has mixed moments of brilliance with typical freshman inconsistency.
He was all but unguardable at times in a 69-68 overtime loss at VCU, where he led the Tribe with 22 points. He also went 0-for-8 from the field and finished with three points in Thursday's 59-47 loss at James Madison.
Still, Thornton is the Tribe's second-leading scorer (11.5 ppg). He is second only to McDowell in minutes and has attempted more shots than any Tribe player, though that's more a product of circumstances than selfishness. The team is offensively inconsistent, owing to injuries and spotty play individually and collectively, and he's capable of creating his own shot when the system breaks down and the shot clock winds down.
"The main thing I've struggled with in the transition from high school to college is how often teams take charges," Thornton said this week. "In high school, when you go to the basket, you either get your shot blocked or people get out of the way. In college, even we stress it here, if someone is going to the basket, take a charge."
Thornton has started the past 10 games, a privilege that Shaver said he had to earn, talent or not. Indeed, he has become a better team defender and is more judicious with his shot selection. Shaver often uses the word "coachable" to describe him.
Thornton is hard to miss, standing in a layup line or in action. He is quick, shifty and confident, unafraid to take a shot or venture into traffic around the basket.
Some of his shoulder-length braids are tied off and seem to sprout from atop his head, so that they don't impede his vision.
Thornton has had long hair since fifth grade and is loath to cut it. He said that he grew up intrigued by Allen Iverson and his elaborate braids and longer hair, then unique among NBA players.
"It's been with me for so long, it's kind of a part of me," Thornton said. "Not a lot of guys have it. I think it sets me apart on the basketball court."
When Drexel coach Bruiser Flint told Thornton that he'd have to cut his hair if he came there, the Dragons were suddenly less appealing. Thornton asked Shaver on his recruiting visit if he could keep his hair.
When Shaver said that hairstyle wasn't an issue, Thornton said, "That was a big relief for me."
"He did ask the question," Shaver recalled, "but I was sold on the young man. There's no question he's a great kid. We've always wanted our teams to look neat, but I can't afford to be old-fashioned on what looks neat."
Thornton was something of a recruiting steal. He didn't get a chance to showcase his skills until his senior year at Bishop McNamara, in the tough, Washington, D.C., Catholic League. He played on the powerful D.C. Assault summer programs, but mostly rode the bench on a roster chock full of Division I talent.
Former W&M assistant Jamion Christian identified Thornton early, and Shaver was sold on the kid's ability, character, family and smarts. Thornton signed with the Tribe during the November early period of his senior year, so that he was taken by the time he began to blow up and attract further attention.
"I figured at that point in time, they had shown me the most love and recruited me the hardest," Thornton said, "and I didn't want to have this mediocre season and lose what I did have. So I thought it would be best to go ahead and secure it and then play my senior season carefree and have a good time."
"You've got to get lucky sometimes, to find kids before the world knows about them," Shaver said. "But I think the other thing that Marcus and his family will tell you is that this is a great fit for him, whether Duke or other big programs came in later or not."
Thornton is well aware of the lack of basketball tradition at William and Mary, but he knew the level of play within the CAA, and he followed the Tribe team of two years ago that won 22 games and went to the NIT.
"That let me know that if you get the right group of guys together, you can have success here," he said. "That kind of helped me realize that even without a great tradition, they could still put together a good basketball club and do great things."
He is disappointed, but not discouraged by a team picked to finish in the middle of the pack that's won only four games.
"You've got to continue to look to get better," he said. "You can't hang your head and give up on the season. We still have (eight) games left. We've come a long way. Early in the season we were losing by 20 or 30 points and now we're playing two-point games. It's just a matter of us making that extra push."
WHO: William and Mary (4-18, 2-8 CAA) at Old Dominion (13-9, 8-2 CAA).
WHEN: 4 p.m.
WHERE: Constant Center, Norfolk.