As the voices get close you hurriedly put your free arm back in and feign sleep.
The two men come in, their voices drop.
"Good, it's asleep that'll make life easier, we'll undo the straps on its wrists to drive the nails through"
"No. it could pull it's hands down... have you not impaled anyone before?"
"Nope usually just say a prayer to Bhaal and stabs 'em, I got a farm to run, not much time for torturing in a day"
"Fair enough, right here's how it goes"
"Now the legs are a bit of an issue if you don't want to break bone.."
You can get the nail with your free hand and do one action