It's almost as if you had 2 questions. It it safe to turn it off, your choice, it won't harm anything. As for the image, if you use Acronis or Macrium for imaging there is no need to turn it off. Do you know/have your key?
its also windows 10 alsoi installed the macrium software on that laptop and created a recovery USB from that laptopWhat's the OS of the other system? What did you use to format the USB boot?