Can somebody give me ONE reason why this couldn't have been done in one day? Just one reason.
I know 500 people is a lot, but they are not all in the same place nor department, so it can't be logistical or lack-of-time related reason.
And if it's not that, what is it???
Because the terminator needs to change his shorts and calm his nerves between each firing.
When a company stretches this process out over a longer period of time, it increases the number of people who will leave voluntarily, with no directly monetary liability to the company. This also has the effect of accelerating the erosion of workforce morale and productivity (not a winning strategy).
Galhotra should be fired for that follow up email. You can't display that much incompetence in corporate communication and bad effect without a hammer coming down hard. That was absolutely incompetent for someone at that level with his responsibilities.