'One day I asked myself if this was what I wanted to do for the rest of my life. I started thinking about brushing up my qualification by going back to school to redeem myself,' he says.
But there's a big gap between 'thinking' and 'doing'. What finally pushed him into action was when he went for a job interview as an office assistant. The prospective employer looked at his results and asked: 'What makes you think I should give you the job?' The degrading experience made Lui realise he needed to make some big changes in his life.
'I once dreamed of becoming a teacher, priest and social worker, but then I couldn't even get a job as an office assistant. I had to pull myself together,' he says.
But the zero was not going to be a setback for him. It would serve as a wake-up call. Filled with determination to achieve his original goals, Lui attended night school and retook Form Four. He scored good results.
'I decided to become a full-time student when I reached Form Five. I was really devoted to studying. I went to tutorial classes for all the six subjects that I took in the HKCEE. I was extra attentive in class. I recorded all the lectures on cassette tapes and listened to them,' he says.
He took his HKCEE again in 1993, and scored 19 points.
Lui says he was filled with emotion when he received his results. His efforts over the previous few years had finally paid off. The magic 19 marks spurred him on to greater things. He completed his A-levels, achieved first-class honours with a social science Bachelor's degree from Baptist University and received his Master's degree and Doctor of Philosophy.
He believes his story can inspire others. Failing HKCEE or not getting into university is not the end of the world.
'In my opinion, students need at least 20 points in HKCEE to have a good chance to get into a university. If you do not have a good shot at a university place, you might as well go for a higher-diploma course or opt for vocational training to boost your competitiveness,' says Lui. 'Life is not all about getting certificates; putting one's talent into good use is the most important thing.'