Dulaney's Gary Bernardez inbouded the ball to Harrelson to run out the clock.
Dulaney's fans stormed the court when the buzzer sounded.
"Did we spin our wheels early?" Lochte said. "I would say so. But we had unbelievable third and fourth quarters (43 total points). At halftime, the coaching staff challenged the team to play for the guy beside them and not for themselves."
Senior point guard Brannon Johnson led Catonsville with 21 points and senior forward Antwann Pearson finished with 15 points and 11 rebounds.
Catonsville coach Matthew Fannon, however, mostly likely remember how his team ended the contest.
"We talk about it in every game: How important layups and free throws are," said Fannon, whose Comets went 11-for-25 from the free throw line. "But also just cherishing every possession and especially in tight games like that."
Dulaney (18-4) trailed 38-23 late in the third quarter, but closed the period on a 9-1 run.
After Catonsville's Jeffrey Sewell hit a three-pointer on the first shot of the fourth quarter to move the Comets ahead 42-32, Dulaney put together a 12-2 spurt to tie it at 44 midway through the quarter.
Bernardez ended the run with four consecutive free throws.
The game was tied five more times in the fourth quarter before Sheppard, a junior forward, sank one of his three 3-pointers to give Catonsville a 56-53 advantage with 1:40 left.