1. Talk to him about Discount.
2. Go to the North-East corner of Gabtown.
3. Investigate, then go downstairs using 'E' or the sidebar button.
4. Go South to Security. Deal with it however. I have no idea if getting caught has any real concequences.
5. Go back North and East. Fight the enemies.
6. Go back to Malai.
I advise not doing it until 0.9.063 because he's supposed to give some extra Credits, but doesn't.