Above the mantelpiece, where else? Seriously, I just threw that in because most people have a clock (or several) and ISTM that you would experience a forward jump in time if this hypothetical device could work as described. Not having read the paper yet, I don't know if it would only work for people observing things from a particular perspective, or whether it would just create a bubble of 'extra' time for anything within its field, during which observations from outside would be impossible. Of course, this might make it impossible to escape as well - I took some dramatic liberties with my scenario to explore the possibilities, although I left out some of the wilder ones that came to mind.