Are you not able to enter any command on the bluetoothctl environment? Or are you just not able to close the environment without Ctrl+Z?
In case it is the former, then it looks like there might be something wrong with your board's OS, so I'd suggest you to use Flash Tool Lite to flash the latest image. You can find Flash Tool Lite, a guide on how to use Flash Tool Lite and the latest image in Intel® Edison Downloads.
In case it is the latter, then you can close the bluetoothctl environment with the command "exit", I've updated the document to add this note.
Let us know which one was it