[ Good thing Spike is bff's with a tech witch then, isn't it? Maybe they don't have the resources of Torchwood but that's nothing new when it comes to him and if Rebecca is game (he has no reason to think she'd object) maybe they can rig something up, starting with: ]
A panic button. The communicators take too long and even if you'd be able to send a message off, it's too obvious. If it was me, that would just make me want to kill you faster. [ Sorry. ] I was thinking something small... something you can keep in your pocket or on your wrist. Something easy to press without getting noticed.