The 2nd key can maybe send the BTC to an another wallet ? So they can't acces to the coins anymore...
That would be great, but how do you achieve that without internet connection, and without any code being executed from inside the wallet?
EDIT : Not mentioning people like FBI could easily setup a sandbox network looking like the internet, and just capture all the streams to check what your wallet is trying to attempt before letting it go live.
If, for exemple i'm with Bitcoin-qt and i send 1 btc to an adress. If i'm not connect to the internet, bitcoin-qt will wait the connection to synchro with the network, but no more option for cancel the sending no ? And for someone took the btc or use the wallet after he acces to it he have to connect to the internet so...