The Burial of Jesus

Even to this day, the world is full of people who are 'secret Christians' who believe in the Lord Jesus Christ, but who keep that faith secret because they are afraid of what might happen to them if the government, or their neighbors, or even their family were to find out.

The same was true during the ministry of Christ, he had secret followers as well, but in these verses we read about a crisis that prompted two of those followers to 'come out into the open' about their faith. What happened that caused that great change?