Just five days into the job, 26-year-old April Cachia arrived for her night shift at Shoreditch fire station.
Hours after arriving - and having never before battled a fire before - she found herself face to face with one of the most devastating infernos in British history.
Miss Cachia, who helped more than 20 residents of the high rise block escape, has told The Daily Telegraph of the harrowing scenes that awaited her at Grenfell Tower.
"The smell of smoke, the sound of crackling, the sound of debris hitting the ground, children screaming, people handing you their phones to speak to their loved ones - they're the things you won't ever forgot," said Miss Cachia, who had dreamed of being a firefighter since she was a child.
From the moment she heard a lady's voice ringing through the fire station just after 2am saying "Mobilise! Mobilise!" Miss Cachia said she knew it was a going to be a big job.
"Our guvnor explained to us that it was a 40 pump fire, which means 40 fire engines need to be at the scene," she said. "That's such a rare occurrence that we kind of all just looked at each other and thought 'wow'. I didn't have anything to compare it to - this was the first proper job really where I have seen actual flames".
Speaking from her home in Bethnal Green, east London, where she lives with her mother Vivien, a 62-year-old retired council worker, and her older brother Damian, Miss Cachia told she could see the block was "completely engulfed in flames" as her crew approached it.
"Along the way I've got my crew around me and they know I'm five days into the job," she said. "They explained that they've never seen anything like this, and we should stick together. [They said] make sure that you just keep your wits around you, be slow and steady, take your time, you know what you've got to do, don't get carried away, don't try to run in and do crazy things."
Miss Cachia described the chaotic scene they were greeted with at Grenfell Tower. "There were lots of people screaming in the streets that their family are inside, that they can't find them, that people are missing, they want help," she said.
"You try and block out as much of your emotion as you can so you can do the best job that you can. It was absolute chaos. I think at this point the police were still trying to get the streets under control".
Miss Cachia's crew were told that the stairwell was too narrow for more fire fighters to come in wearing the full breathing apparatus suits, so they were given the option of helping survivors outside the building, or going inside with just with eye gear to help residents flee to safety.
"My partner Paul and I just looked at each other and said shall we just get in there?" she said. "At this point there are loads of people coming out so you've got hope and you're excited and you're like, yes we are saving people. And then slowly as time goes on the numbers stop coming it gets quieter and quieter."
Miss Cachia described how at first, she was helping residents flee down the stairs every few minutes or every 30 seconds - and then there was a period where no one came down at all.
"It would have been about 45 minutes, and that seemed like forever," she said. But after fearing that all the remaining residents had perished in the flames, suddenly an Asian family of four appeared on the stairwell.
"It had been so long since we had heard from anybody, it was unbelievable that this family just came out," she said.
"You could tell they had been up there fighting for their life. I just thought thank the lord, that's one more flat that we can just cross off."
Miss Cachia told of another woman who, while she was still inside the smoke filled building, stopped to raise the alarm about her blind neighbour who alone and trapped in his flat.
"That woman was so courageous, she had been choking and crying and screaming but stopped and shook me to tell me," the 26-year-old said. "She just really cared for him - that unity of the neighbours in that block, you could tell they were such a close community."
Miss Cachia said she sent out a priority message about the blind man, and later heard that he had been saved. She spoke of the bravery of her colleagues, who took off their helmets to shield babies from the smoke.
"You've got babies being bought out and firefighters, putting their helmets on the children so that they can be safe. If they didn't have a spare one they would have taken theirs off and put it on the child," she said.
Miss Cachia, who had just completed her 11 week training course, said she was in Grenfell Tower for an "awfully long time".
"We started helping people on the third floor, but we ended up on the tenth floor," she said. "You want to get to them, so you end up going higher and higher.
"People are saying 'I know my brother, my sister, my aunt are still in there'. You are so blinded by how serious it is, that you just get on with it and do the best you can. I've never seen so many people work so hard in all my life."
Miss Cachia said she is thinking of all the families and praying for them. "This hasn't put me off the job at all, if anything it has made my hungrier to carry on," she said.