How was Raiden able to get through the nano machines in the Armstrong fight?

[P O P]

Besides the obvious requirement for the protagonist to win, how was he able to do it? If the nano machines "harden in response to physical trauma" or whatever Armstrong said, how was Raiden able to stab him through the gut and then chop out his heart? We know from the Sam vs. Armstrong fight that it is possible if you can strike before they harden, but we also saw that they seem to start hardening at the heart, then spread to the piece of flesh that needs protection. The gut would be faster to reach than the forearm and Raiden didn't stab him in the fast mode (I haven't played in a while and forgot the actual name). Also, wouldn't the heart just immediately harden? I know that Raiden's whole gimmick is that he is very fast when he is in the blade mode, but like previously mentioned, the game showed that they first harden around the heart, along with hardening before the strike even connects, so pretty much no matter how fast Raiden moved, the heart should of already of hardened.

I know that I'm overthinking everything, but I just re watched the fights and couldn't help wondering. Also, if this is mentioned in some random lore entry, sorry about writing this post, because I simply never read those in any games I play.

[The Snek]

It looks like he can just control the power at will also Raiden was just too fast of an attacker to make mini-cuts and literally chip and scrap away nano machines and further injure Armstrong. It looks like his heart was like the source to his nano-machine ability to self repair and for nano machines to multiply. to make any sense, they somehow could've been organic and synthetically-organic to just do their job as repair units

[Der Ausländer (Sulos)]

Maybe the reason isn't that deep. The fight was long and intense, perhaps at some point the nanomachines could no longer keep up.

[Orangeninja]

Raiden's original blade could not punch through the machines, but the Murasama can, as when a sword is converted to an HF blade the power of the blade is dependent on the quality of the original blade, as stated in the Murasama's lore entry.