They frantically pounded their sticks on the boards, trying desperately to get the attention of officials.
Then the Dallas Stars players took matters into their own hands and jumped onto the ice while the game was still on.
Rich Peverley, a teammate with a history of heart trouble, had collapsed on the bench.
"When he dropped, it was red alert," Stars coach Lindy Ruff said. "Don't worry about the game. It was about getting the doctors. The players don't want to play, and I don't want to coach the team right now."
He didn't have to.
So rattled were the coach and team that Monday night's game between the Stars and Columbus was postponed with the Blue Jackets leading 1-0 in the first period.
The 31-year-old forward was taken to a Dallas hospital and was in good condition. But there was little such assurance earlier in the night.
Once the game stopped, the Stars players stood in silence, clearly in distress, wary of what happened to one of their own. Some players from both teams dropped to one knee on the ice.
"I was scared," Ruff said.
Forward Erik Cole tried to rush into the tunnel just after Peverley was carried through, only to be turned away. He gnawed at the thumb of a glove while he waited for word on what would come next.
Sergei Gonchar stared blankly near fellow defenseman Trevor Daley, who was hunched over on the bench, wiping his face with a towel.
Six months ago, Peverley underwent a procedure to correct an irregular heartbeat after a training camp physical revealed the condition. He missed a game last week with a recurrence of the problem.
Dr. Gil Salazar of UT Southwestern Hospitals said Peverley was treated Monday night for a cardiac event at American Airlines Center.
The Dallas Stars tweeted that Peverley was successfully treated.
Dr. Gil Salazar of UT Southwestern Hospitals said Peverley was treated "successfully" for a cardiac event at American Airlines Center.
"We provided oxygen for him," Salazar said. "We started an IV. We did chest compressions on him and defibrillated him, provided some electricity to bring a rhythm back to his heart, and that was successful with one attempt, which is very reassuring. As soon as we treated him, he regained consciousness. He was able to tell me where he was."
Play was halted at 6:23, and the postponement was announced about 30 minutes later.
"The first thing (Peverley) asked me was how much time was left in the first period," Ruff said.
Many in the hushed crowd lingered long after the postponement. The announcement cited the "emotional state of the players on both teams caused by the medical emergency." The NHL didn't say when the game would be rescheduled.
Peverley's wife, Nathalie, accompanied him to the hospital, and the Stars told the Blue Jackets they weren't up for finishing the game.
"They're shaken and they want to reschedule. We understand that," John Davidson, the Blue Jackets' president of hockey operations, told Fox Sports Ohio. "They were shaken to the core."
Peverley missed the preseason and the season opener after the procedure during training camp. He made his Stars debut Oct. 5 against Washington.
"We monitor him closely for a different type of arrhythmia he has," Salazar said. "He does have a pre-existing condition, and the condition -- a normal quivering of the heart that does not allow him to send blood to places where he needs to, in his brain and heart."
Peverley sat out last week's game at Columbus and couldn't fly because he felt strange. But he played in Dallas' next two games before Monday.
"There wasn't any concern," Ruff said. "Our doctors have done a fabulous job monitoring the situation."
In 62 games this season before Monday, Peverley had seven goals and 23 assists. He was acquired last July from Boston with forward Tyler Seguin and defenseman Ryan Button for forwards Loui Eriksson, Reilly Smith and Matt Fraser, and defenseman Joe Morrow.
The Stars went to the airport after the postponement, headed to St. Louis for Tuesday night's game against the Blues.
"He's going to be OK," Ruff said. "The care he's getting and the care going forward is the most important thing."
NBC 5 DFW's Ray Villeda contributed to an earlier version of this report.