"I went back to my training where they taught us to just take a deep breath, think about what you're going to do and just do it," Tully said.
Tully did not have to reach too far back to recall his lessons from the academy — it was his second week on the job.
When Tully, 28, signed up to be a Prince George's police officer, he knew the work would be anything but routine. The rookie was not expecting to jump into what might be one of the most memorable calls of his career on his 14th day of duty.
Tully made headlines Sunday after he fell through a sheet of thin ice while trying to rescue three men who slipped into the pond. Days after the dramatic rescue, he and his field training officer, Rion Robinson, 27, detailed how they jumped into action as the first police officers to arrive on the scene.
Tully and Robinson had been on patrol in the Lanham area when a call came over the radio for a drowning child less than a mile and a half away.
The pair rushed to Glenridge Park in Riverdale, where it turned out it was three men who had fallen into a pond.
The officers ran out and screamed to the men, who were about 20 yards away from the shoreline.
"Can you touch the bottom?!" Robinson recalled yelling.
They could not. All three were treading water and struggling to stay afloat, with one man who was near drowning.
"We realized it was a life-or-death situation," Robinson said. "I said to Tully, 'We're going to have to drop our duty belts and go in.' "
Robinson and Tully unlatched their gun belts, radioed to incoming officers they needed rope and immediately stepped on the icy pond.
As they made their way out, Tully got down on his belly to distribute his weight. He crawled closer to the men as Robinson passed along a vine relayed from witnesses on the shore.
"Robinson threw it to me, and I threw it to a guy who was drowning," Tully said.
Tully continued to crawl to the end of the sheet of ice on the pond where he met one of the men who was especially panicked. In a splashing, frantic state, the man pulled Tully into the freezing water.
"It was a scary moment because I still had my vest on and my boots on," Tully said. "Those things weighed me down."
Startled, Tully realized he needed to stay calm. He took a deep breath and slowly pulled himself back up onto the ice, trying not to break through again.
He re-extended his arm to the man who had dragged him in.
"Don't pull me back in," Tully told him. "Hold on to my hand."
At the same time, one of the other men saw how Tully had pulled himself out of the water and started doing the same.
"I encouraged him to keep going," Tully said.
When Tully looked up, he realized "the whole world came" as firefighters and more police swarmed the scene.
"[Firefighters] came and threw Robinson rope, he threw the rope to me, and I threw it to them," Tully said. "I got up, and we all pulled them out."
Robinson, who has been with the department for more than five years, said there was no question he and Tully would go out on the ice.
"There was no telling how long they had been in the water," Robinson said. "It's a life-or-death situation . . . at that time, it was time to go in and in a sense, put ourselves in danger."
Tully was sent to the hospital to be checked for hypothermia. He wanted to change his uniform and finish his shift after doctors released him, but he had to go home because his vest was still wet from the rescue.
Tully comes from a line of firefighters and always knew he wanted to be a first responder, but he said he figured something as dramatic as Sunday's rescue would not happen until he was a veteran.
"Jumping into something like this is crazy," Tully said. "I know it's a moment you can't top, but I want to do bigger and better things. I want to keep doing good and making the department the best."