A Grenfell Tower resident was told to remain in their flat, despite the fire brigade having ordered everyone to evacuate 15 minutes earlier.
Emergency staff taking calls from residents in the tower on the night of the 14 June fire were unaware advice had been changed, the inquiry heard.
Richard Millett QC said the control room operator "had not yet been given the message".
Other residents also received different advice on whether to stay or go.
Seventy two people died as a result of the catastrophic blaze in the 24-storey tower block last year.
Initially, the London Fire Brigade's advice to residents was to stay put and remain in their homes - on the understanding that they would be protected by the building.
But as the fire escalated out of control, residents were encouraged to "escape by any means necessary", rather than await rescue.
Call records show that people phoning within minutes of each other were given conflicting advice, even before the fire brigade decided residents should evacuate at 02:47.
At 01:28, one caller was advised to "get everybody out". But a minute later a different caller was told: "There is someone coming up to help you."
"There is nothing else I can do other than tell them that you're there," the call handler told the resident. "They are aware that you're there."
Metropolitan Police Commander Neil Jerome defended operators manning the phones in Scotland Yard's control room, saying they were reviewing each case individually and "making an assessment".
"They are making these flexible decisions based on what they are hearing at the time and clearly not rigidly adhering to the advice that had been given to them," he told the public inquiry in London, on Tuesday.
'Tell me where you are'
However, Commander Jerome could not account for why another resident who called at 03:05 - 18 minutes after the stay put advice had been dropped by the fire brigade in favour of immediate evacuation - was told help was coming.
The operator told the resident: "I'm trying to get someone to you but you need to tell me where you are."
The inquiry heard the change in advice did not go out over the police radio until 03:08.
"That particular control room operator had not yet heard or been given the message the advice was now to evacuate," said counsel to the inquiry, Richard Millett QC.
The lag in communication between the two emergency services could not be explained, Commander Jerome said.
PC Josh Rees, who was one of the first officers on the scene, said he felt "helpless" when he heard the message that people were to "self-evacuate" over the radio.
"I could see people in the windows of the tower trying to get the attention of emergency services with lights, opening the window - and all I have been able to do is watch as the fire has moved towards them."
"I felt so angry that there was nothing I was able to physically do."
"Stay put" was eventually removed as the official advice to residents one hour and 20 minutes after the inquiry's experts say it should have been abandoned. Only 36 people managed to escape after that point.
The public inquiry continues.