Knowing Gus all the Germans will get it because they'd talk if just one were killed. Then that sets the stage for the lab in BB to be an even creepier and evil place. Maybe we find out they were dead men from the start.
Agree. Knowing Gus from BB, I had that thought from the very beginning. Once they complete the project, there's always the (good) chance that they start talking about 'the big American project' they worked on once they return to Germany. Gus can't (won't?) take that chance.