TAMPA, Fla. (WFLA) — When Gael Macleod read the text message, she froze.

Then, she read it again. And again. And again.

This text was clearly intended for someone else, she thought. It’s contents were too awful to be true.

“Mistakenly sent to me,” she reasoned. But, that wasn’t the case.

This message could only be hers. The sender was her son.

His words shattered her heart. All at once, she wanted to scream in anger, sob in pain and collapse in despair.

Her teenage grandson had just witnessed a mass murder in his own school, his classmates shot to death in Parkland Wednesday.

Jack Macleod could have been one of them.

Before the day was over, the high school junior would run for his life. He would find himself panicked and scrambling among hundreds of students to find a safe haven – a classroom.

There was no hesitating, no pause. Time was running out.

The gunman was on his rampage, and the students were his targets, young lives who knew their survival depended on finding a place to hide.

The only option was to find it fast, and most of them did. They heard gunfire growing closer.

All they could do was watch, wait and listen.

Jack was trying to make his way back into the school after the gunman made his first move – a cruel, devious strategy where sources say he pulled a fire alarm knowing the students would empty the classrooms – into the hallways.

The students would be in the open. No protection. No defense. They would be helpless.

Jack was among those outside who then began to run back in as they realized what was happening. Jack knew exactly where he needed to go. He had to get back to his homeroom class. That was his safe haven.

Clutching his cell phone, he knew if he could make it there, his teacher would lock the door. They would be safe inside. They would wait.

Jack could hear the sirens. He knew police officers were nearby. All he had to do was make his way through the crush of students.  His classmates were frantic and scattered.

Jack said he kept thinking, “Get to the door. Get to the door.”

Searching, running, racing against the clock. Got to get to the door – and then he did.

Then, the high school junior felt a wave of hopelessness wash over him. It was a twisted moment of victory and defeat.

The door was shut. And locked.

Jack knocked loudly and stood there. He said his head felt like a rapid swivel – back and forth. “Where was the gunman? Was he close?” he thought.

Jack’s shaking hands curled into fists as he began beating on the door.

“PLEASE, PLEASE,” he shouted. “Please let me in. Open the door!”

Jack would later tell his mom and dad that he heard his teacher’s muffled voice. She sounded frantic. Stern. Urgent.

The door would stay locked. And Jack was on the other side, alone. He was away from his friends, classmates and teacher. From his comfort zone.

And a gunman was approaching.

Jack’s teacher yelled back through the closed door. She told Jack that she could not unlock it. Under any circumstances.

But, she was quick to follow with Jack’s next step.

Her instructions were clear. And, she knew he’d follow them him without hesitation.

“Go find another classroom,” she said. “NOW.”

The teacher told Jack to find an open door and shut it behind him. She instructed him to lock it and said to not even think about opening it until police arrived.

Jack stood on the other side of the door, by himself, listening.

That detail broke Gael. A mental image she couldn’t bear. She knew this day was horrific. She knew all the firsthand accounts would be both grisly and heartbreaking.

But, when the Tampa grandmother heard the stark description of her grandson, scared and confused, coming face to face with a closed door, she broke.

It was more than she could bear.

“My stomach hit the floor. It hit the door. Then, I began thinking about all other children,” Gael sighed.

She paused for a moment, then added, “I ache for them. My heart aches for them.”

It is a difficult place to be mentally, she explained. Conflicting emotions seem to present themselves in rapid succession. Amidst so much pain, she also feels relief.

Her grandson was spared. He would survive a day so many others did not.

Jack eventually found a room filled with fellow students huddled together. He raced in, and the door shut behind him. Locked. Not to be opened.

He was now on the inside where he remained for more than two hours until SWAT teams broke down the door, rescued the children and led them out of the building.

These children were massacred. They were targets by a gunman consumed with evil. Their families will deal with heartache for the rest of their lives.

Gael is reminded of the advice she so frequently offers others, which is to never pass up the chance to tell those closest to you that you love them. Remind them, she says, what a difference they make in your life, how important they are.

It’s a practice near and dear to Gael. She can’t wait to tell Jack.An official GoFundMe campaign has been created by the Broward Education Foundation. The funds raised will be used to provide direct relief and financial support to the victims and families following the shooting in Florida.RELATED COVERAGE-