Her sister in a phone call then advised her to leave but by that time she found her escape route blocked as flying embers had set fire to her building too.
She was forced to climb out of a window, get on to a shop parasol below before jumping into the arms of a policeman.
Craig Street, a painter and decorator, also filmed Thompson allegedly setting fire to the furniture store after saying “let’s burn the place” or “let’s torch the place” and asking “Who’s got a lighter?”
It is alleged Thompson, who is said to have attempted to disguise his identity by wearing a hood, then stood watching as the store blazed.
The Old Bailey heard Thompson, who had already looted a laptop from the store, went back inside in an “act of cynical cowardice” and caused the catastrophic blaze which spread within minutes.
As sparks and intense heat set buildings opposite alight, householders were forced to flee for their lives – with “some were lucky to escape at all” including Ms Konczyk.
The prosecutor Oliver Glasgow said: “She heard smashing glass and she went to investigate and saw hundreds of youths running along the street.
“She saw people looting electrical goods from Argos and forcing their way into a supermarket to steal alcohol.
“Not long afterwards she realised someone had set fire to a bus and then she saw a group attacking the front of the furniture shop.
“She saw a man run into the shop and place something square on a piece of furniture inside, which he then lit.
“Whilst this was happening she stood in the mouth of her entrance to where she lived. She had the presence of mind to film what she saw unfold before her eyes.”
He added: “If there is any lingering doubt, the person captured on her phone was the defendant.”
Before the arson attack, Thompson played a “leading part in the disorder” having looted both Iceland and House of Fraser before finally targetting the furniture store on Reeves Corner on August 8 of last year.
The jury were told Thompson admitted these two burglaries but has denied breaking into House of Reeves, one count of arson with intent to endanger life, one count of arson recklessly endangering life and violent disorder.