A few people had gathered, and one older man was out on a small paddle boat trying to slide closer to the dog.
"I stripped down to my boxer briefs, took off my uniform and my hat and everything, and left my socks on knowing how sharp ice can be," Arens said.
Then Arens got into the boat and tried to distribute his weight so that the ice wouldn't crack from under him as he made his way closer to the dog.
"I could see through the ice now because it was really thin," he said, "and I could see three-quarters of the dog's body was underwater — just her head was up and barely out of the water."
Then Arens got out of the boat, holding onto it with one hand and trying to reach the dog with the other, all while balancing on the thin ice.
"My biggest fear was falling through the ice and not being able to get out," he said.
Sure enough, the ice broke.
"I went down, and at that point, I just swam out to the dog and grabbed her collar — thank God she had a collar on — and swam back to the ice," Arens said.