Putting this plastic part in the back of the printer proved to be the most difficult part of the process. My colleague Erin Carson and I had to shave down the end of one side with scissors to fit it in the hole.
We didn't use the glue the first time around (which ended up being a good thing, because it messed up the prints) so the robot was stuck to the glass. A quick Google search showed that this is a common problem, and a few minutes in the freezer helps objects pop right off. It worked.
One of the problems with the printer is that when the extruder was knocked off course, or the plastic didn't stick to the glass plate well enough, it continued to print. That problem could be fixed by some sort of sensor in the nozzle head.