A truly general AI, though, almost by definition, would be able to think up countless ways of overpowering you. It's very unlikely that you could adequately guard against all of those ways, and the AI only needs to succeed once to cause an existential risk.

It isn't likely to be you vs the superintelligence, though. People keep imagining that - and then wringing their hands. The restraints on intelligent agents while they are being developed and tested are likely to consist of a prison built by the last generation of intelligent agents, featuring them as guards.