at the back , in a special velcro pocket , were her special supplies - the vampire-related ones : a couple of heavy , silver-plated stakes that she hoped never to have to use ; a couple of injectable pens that she and myrnin had rigged up with the serum dr. mills had developed , just in case there were still a few vampires around who had n't gotten the shot and might be - to put it kindly - unstable .