Marie Curran, who was working on the jail's N wing, told a jury how she spotted a needle in an inmate's hand shortly before the theft of a set of keys led to a "mad rush" to evacuate the block.
Four inmates - Luke Mansell, 24; John Burton, 39; Carl Brookes, 33, and Ross Queen, 30 - are on trial at Birmingham Crown Court after denying taking part in a prison mutiny on December 16 last year.
Giving evidence as the trial's first witness, Miss Curran said disorder at the prison began at around 8.30am when two other prisoners who had walked past her made their way onto "trampoline-like" netting on the fourth floor.
Miss Curran said of the men: "It was like they seemed in a rush, stomping if you like. They were both just walking, head forward, face down. It was like they were walking with a purpose.
"They walked past me and I watched them go up to the fours (the fourth floor) and walk straight on to the netting."
A decision was then made to lock everyone in their cell while the problem was dealt with.
Miss Curran told the jury: "It was just getting increasingly volatile.They were all shouting, running from one end of the netting to the other.
"It was as if they were warming up.
"They were armed with table legs - some metal, some wooden - and they started to take off their T-shirts and were waving the weapons around. Tables were getting thrown onto the netting."
Describing how she had filmed part of what happened with a body-worn camera, the prison officer added that one inmate was smashing smoke detectors and lights, and another damaging items with a piece of wood.
Burton smashed a glass window, said the officer, who went behind a locked gate as colleagues began to change into protective equipment, including shin pads and helmets
Recalling the moment she was told a set of keys had been snatched, she told the court: "All of a sudden someone said 'quick, get off the whole block' as they had a set of keys.
"Everybody was panicked, everybody tried to get everything they had. Some people were in the middle of getting dressed. It was just hectic.
"You could just hear shouting (from the prisoners) - the noise level on the wing just kept increasing and increasing.
"There were trays, TVs, paper, food - things being thrown out of the window and than a short time after that there was smoke coming out of one of the windows on level two."
The court heard on Monday that the keys were used to free around 500 inmates from their cells.