Deslauriers tied it 2-2 at 2:23 of the second with a shot from just inside the blue line. Roy then scored two goals in a 3:05 span to give the Golden Knights a 4-2 lead.
He made it 3-2 at 3:49 when he scored on the carom off the end boards after Shea Theodore's shot went wide, and 4-2 at 6:54 when he got to a loose puck and scored from the slot. He had not scored in the previous 15 games.
"It was nice, some guys got off some streaks, like Nick Roy," Vegas coach Peter DeBoer said. "He'd been snakebit for a while. We were due, some of those guys were due, and they went to the right places in order to score."
Amadio pushed the lead to 5-2 at 9:44 when he redirected a centering pass from Chandler Stephenson.
"This is a three-goal league, if you score three, you've got a chance to win," DeBoer said. "It took us five tonight, but we'll take it. Two desperate teams going at it out there, a hard-fought game."
Zegras scored on a power play to make it 5-3 at 18:38, and Terry scored on another power play at 6:39 of the third for the 5-4 final.
"We shot ourselves in the foot in the first part of the second (period)," Anaheim coach Dallas Eakins said. "In the third, what happened, it wasn't that we got our game going, we quit turning pucks over in the neutral zone, simple as that."