It's real easy...
First sentence: A business decision has been made and it affects your job.
Second sentence: The decision is final.
Third sentence: Come with me to HR, they will explain the next steps.
While they are in HR weeping and wailing, pack up all their shit into cardboard boxes and take them out to the lobby. When they are done with HR, HR escorts them out to the lobby and they can't get back into the building.
I actually did this at Intuit during layoffs. Very effective. After this was done, HR asked me if I needed to see a grief counselor. I just look at them and asked why. They said, we thought you might be stressed. I just looked at them and had one word... NO.
I'm sure they thought I was pscyo.