'I knew he wasn't breathing': Staff at Dallas elementary school save man having heart attack

It all went down a few weeks ago, on March 26, after the sub went into cardiac arrest while standing in the front office.

"I heard a thump, so I quickly ran across my desk and came over to check and see how the sub was," said Irene Aguilar, the office manager. "Right after that, I knew he wasn't breathing."

Aguilar began to render aid and called for help from nearby co-workers.

"As I run into the office, I find him laying there, and he's bleeding from his head," said school counselor Amparo Guzman. "I automatically got my cell phone, called 911 and I went to grab the defibrillator."

Someone called over the school nurse, Beata Fik, to help keep the man alive.

"I opened the machine up," she said. "I told them to rip the shirt off, and apply the pads."

After two shocks from the defibrillator and taking turns administering CPR, the sub finally regained a pulse.

That teacher is now doing well on his road to recovery, and if there were ever any doubts before, now you know that teachers and nurses will always have your back.

"We're devoted to this job," Guzman said. "Not just the kids, but everyone who walks into this building."