Ah, the Eisenstein movie...
I'm not talking about the Eisenstein re-imagined movie, I'm talking about the book. Written by the journalist you cite below.
Anyway, I was mistaken. The incident involving a small number of Red Guards accidentally finding an unguarded back door by the river appears in Trotsky's
History of the Russian Revolution. The Guardsmen stumbled into a room full of unarmed cadets, tried to arrest them, and were in turn stumbled upon by lots more armed troops further into the palace, and were themselves disarmed.
There weren't any cadets present AFAIK. In fact, there was no mention of any military in the whole documentary of the "event" - except for the part of the supposed red heroics ofcourse.
What "documentary?"
Reed explicitly describes a standoff between Red Guards/armed workers and cadets manning a machine gun by the front gate on Palace Square. The following exchange comes directly from his book:
Like a black river, filling all the street, without song or cheer, we poured through the Red Arch, where the man just ahead of me said in a low voice: "Look out comrades, don't trust them! They will fire surely!" In the open we began to run, stooping low and bunching together, and jammed up suddenly behind the pedestal of the Alexander Column.
"How many of you did they kill?" I asked.
"I don't know, about ten..."
After a few minutes of huddling there, some hundreds of men, the army seemed reassured and without any orders suddenly began again to flow forward. By this time, in the light that streamed out of the Winter Palace windows, I could see that the first two or three hundred men were Red Guards, with only a few scattered soldiers. Over the barricade of firewood we clambered, and leaping down inside gave a triumphant shout, as we stumbled on a heap of rifles thrown down by the yunkers who had stood there.
As for the Palace garrison, it consisted of cadets, cossacks, and a Women's Battalion. This is well documented.
Reed describes how Kerensky's government had relaxed the admission requirements to the Officer's Academy (which is across the street from the Palace) because of manpower shortages, and how they were rushed into service and armed the night before November 7, when news of the imminence of the revolution reached Kerensky.
As journalist John Reed (who was present at the event) already commented, it was "a remarkably bloodless event". The only mention of shots being fired, were from a cannon commanded by the Reds. No battleships firing. And this at a time when the "storming myth" hadn't been invented yet.
John Reed also describes
Avrora being used as the signal for the closing of the noose in Petrograd on the Palace. Also,
Avrora is not a battleship, it's a small cruiser. You can visit the cruiser, as I have, and see that its guns are still pointed at the palace across the Neva.
I'm not sure a "ten-story battle mech" has to do with anything, but if a battleship fires and the result is some furniture gets broken (not from shellshot, by the way), I wouldn't describe any of the ongoings as heroic. Which probably prompted the need for a "storming the Winter Palace" myth in the first place.
The action of seizing the Provisional Government officials and destroying the opposition to Soviet seizure of power is the heroic action. The fact that it was nearly bloodless doesn't make it unheroic. Rather, I think it makes it
more amazing and heroic, that all that was accomplished without a repeat of Bloody Sunday, in a way that "makes it look easy."