There were at least 4 personal security officers for LKY.
One of my friends who was an MP, invited me to one of his constituency National Day dinners, and he told me that LKY will arrive after the second or third dish.
All attendees were scanned and had to walk through a metal detector.
After he arrived, the 4 PSO stood at 3, 6, 9 and 12 o'clock to cover the area around LKY. No one I allowed to stand or move around. The waiters stopped serving food, until after LKY's speech.