Sentient implies self awareness. I don't think the arm were sentient. They had an artificial intelligence designed to complete the fusion reactor, and clearly designed for self preservation, however they were still controlled by Ock's brain.
Now we see Ock unconcious twice. The first is of course the operating room. Now Ock has presumably been unconcious since the explosion and clearly the arms have not done anything till the moment they attack, and Ock is awake seconds after that. So are the arms working independently, OR is it Ock slowly gaining consciousness that allows the arms to awaken?
The second time is during the final fight. Spidey tricks Ock into stabbing the power cables, thus electrocuting Ock.
This knocks out both Ock AND the arms.
But both are fine as soon as Ock fully regains his capacities.
Clearly the electricity did not damage the arms, as they are designed to deal with high energies, AND there was no mention in the film of their being self-repairing.
So IMHO, if Spidey had knocked him out, the arms would be out too, at least till he starts to come to.