it seems to me that since it was shown that you can put something into the rift and then pull it back (the screwdriver), the simplest of experiments would have been to push a small wired video camera through the rift to see what is on the other side.
assuming that the time displacement of any rift is constant from the point in time that it was created, why not just produce more rifts and then butt them up to the ones that are going to throw up the garbage real soon. that would be a stop gap measure and would give them a bit of time to figure out what to do with the next wave.
what i should really be doing is working right now, though, and not trying to solve problems from a made up short film...