The brick building colored by peeling, fading yellow paint and the word "Facilities" is home to the Haskell Boxing Club on the campus of Haskell Indian Nations University.
Indoors, amid the speed bags, heavy bags and musty odor, Marcus Oliveira ponders a question.
When you hurt somebody badly, and the referee steps in to stop the fight, what's going through your head as you look at that swollen, bloodied face of defeat?
"I think about how all the hard work and training is worth it," Oliveira said. "I think about how if I didn't train so hard, that could be me looking like that. I could be the other guy."
Such is the mentality of every successful boxer. Defend yourself at all costs, even if it means turning your opponent into a bloody mess. It takes more than courage and power and speed. It takes precision of technique. It takes discipline.
Oliveira, 25, estimates on many days he trains up to seven hours, including the running he does on the concrete pathways throughout Lawrence. When he's not working out, he's working at Wendy's, where he's a crew chief.
All of his more than 200 bouts thus far have had one thing in common: He didn't earn a penny for them. That's about to change. Oliveira is scheduled to make his professional debut tonight in St. Joseph, Mo. The Civic Arena doors open at 3 p.m. The mixed martial-arts show starts at 4, and the boxing show begins at 7 p.m.
Club fights being what they are, Oliveira, a light-heavyweight, will not know the identity of his opponent until he arrives.
Even so, Oliveira said he knew one thing.
"I know I'll win," he said. "I'm in the best shape of my life."
Oliveira's first purse will depend largely on the size of the crowd. It will be either small or smaller. (For tickets, call Erik Riley at 979-9115.)
Riley, who trains Oliveira and others at Haskell, enticed Oliveira out of boxing retirement after hearing that he took the sport up at a young age. He invited him to compete in a tough-man competition to get his juices flowing again.
"Once I did that, I wanted to get back in the ring," Oliveira said.
So after a two-year hiatus to play basketball for Haskell, where he received an associate's degree, Oliveira put the gloves back on.
He said he took up the sport at the age of 7, back in his native Keshena, Wis., along with his brother Cory. Marcus said their mother, Debbie, got them started in the sport.
"I don't really think she had any connection to boxing," said Oliveira, who estimates he has lost 23 fights and won about 200. "She just needed a baby sitter for us."
Now it's Riley who baby-sits his boxing development.
"Marcus has a lot of intelligence in the ring," Riley said. "And he's got power and great reflexes. You can't teach power and reflexes."
Oliveira said he used to consider his left hook his most powerful weapon until he suffered a dislocated shoulder in the ring two years ago. That led to his abandoning the left hook for a while until bringing it back. In the interim, he developed his left jab into a better punch.
It all has come together well enough for him to punch for pay.
"This is what every amateur boxer is hoping for," Oliveira said. "A shot. I want to thank (manager) Doug Ward of Underground Boxing (in Elena) for giving me the shot."
As a pro, he doesn't expect that powerful boxing moment, when a silence falls over the venue and the boxers await the opening bell, to feel any different than it has felt throughout his amateur career.
"A lot of butterflies in your stomach," he said. "Then you're wishing that bell would hurry up and ring so you can get this thing over with."