[beeflet]

The obvious answer is to kidnap lightning channel maintainers instead. They will always have their funds living on a "live" computer, which you can extract secrets from using whatever side-channel you like.

This way, you don't even have to torture them. You just have to kidnap them and keep them from transmitting closing transactions.

If you open a channel with them beforehand, you don't even need to extract the keys from their hardware. You get to can steal the funds in their channel unless they use another mechanism like a DMS to transmit a revocation transaction.