There was a boom from somewhere above them, Sam looking up to try and ascertain where it came from.<br/><br/>"We should be up there helping," Sam said, a note of annoyance in his voice.<br/><br/>"You'd be no use to us dead," Myst replied. "If they reach down here you're replicator abilities may come in handy."<br/><br/>He was tapping away at a computer bank in front of him, directing the defences even though he couldn't see what he was doing.