Daniel Egan, a station manager in regulatory fire safety, arrived shortly before 2am on June 14 last year and co-ordinated 999 call information.
He realised “very early on” that the inferno was out of control and urged three senior fire officers to abandon the stay-put advice given to occupants.
A full evacuation was eventually ordered at 2.47am, almost two hours after the fire began.
Mr Egan told the inquiry into the disaster that, as sunrise neared, a crew manager came over with a mobile phone.
On the end of the line was a mother who was in flat 113 or flat 133, the hearing at Holborn Bars was told, while her partner watched helplessly from the ground.
“All she said was...” Mr Egan started, before pausing to compose himself.
“Sorry,” he continued.
“She was saying she just wants to go, really, one of her children had already gone and the other one wasn’t moving and she had no reason to do anything,” he said, his voice breaking.
It is unclear to whom Mr Egan had been speaking.
The officer, with 26 years’ service, also recalled a conversation with a man stuck on the 10th floor, who was a priority for rescue due to his proximity to the blaze.
He said: “The guy was so calm, he just believed we were going to get him out.”
On Tuesday, Mr Egan told the inquiry it was “obvious” that an evacuation was necessary from the moment he arrived.
Asked on Wednesday by counsel to the inquiry Richard Millett QC at what stage he realised fire crews would not be able to extinguish the fire, Mr Egan said: “Very early on.
“There was so much fire that was going through into flats, just on my experience I know you weren’t going to get the water to all of those floors, we just can’t physically do that.
“That’s where my opinion was, we needed to get the people out and once we get them out we could at least then try in a more strategic manner to try to extinguish the fire.
“They were committing breathing apparatus crews to get people out but the frustration was I didn’t know that was what they were doing. I didn’t know if they were trying to put the fire out as well - if they were, they were just wasting resources, wasting time - we cannot put that fire out.”
He had expressed his frustration about the stay-put advice up the chain of command.
He said he raised concerns after group manager Tom Goodall took over responsibility for the 999 calls, a role he had been doing for around 40 minutes since arriving at 2am.
“I was vociferous in the way I said it, I just wanted it to be heard,” he said of conversations with Mr Goodall and group managers Richard Welch and Pat Goulbourne.
“Sometimes some people get focused on their own little routines - I’m sure I got focused on fire survival guidance - sometimes you need to listen to what else is going on.
“You might not see that as the priority, but to me, it was clear.”
Mr Egan explained the system used for prioritising rescues on the night, putting flats with the vulnerable and children first.
At the close of his evidence, he said: “Can I just say - we prioritised everyone, just some were a bit higher.”
A firefighter also described how he tried to text his mother after realising he was running low on oxygen and in “big trouble” in the smoke-logged stairwell.
Christopher Secrett, a crew manager from North Kensington, was among the first at the blaze and initially ran the bridgehead, or safe-air space, two floors below the burning flat.
He later joined firefighters David Badillon and Chris Dorguu on a mission to the 20th floor to rescue stranded 12-year-old Jessica Urbano Ramirez, who died that night.
The team were forced to leave when Mr Secrett’s oxygen supplies began running low in his breathing apparatus.
His statement said: “The smoke was thick in the stairwell and I could not see my hand in front of my face.
“We had all lost our energy. We struggled to get down the stairs and it was a mixture of stumbling, falling and crawling trying to get down.
“After coming down three-four floors I realised we had lost (firefighter) Chris Dorgu. I asked for (firefighter) Badillo to shout for (firefigther) Dorgue because I had no energy to do it. Neither did he. We sat there.
“I looked at my gauge and saw I only had 15 bar left; I was in big trouble.
“I put myself in a corner of the stairwell because I did not want to be in anyone else’s way if I didn’t make it out.
“I tried to get my phone out of my pocket to text my mum but I couldn’t get the phone out.”
Mr Dorgu suddenly appeared and dragged them both down the stairs, he continued.