I have a strictly no food and drinks policy in my car for 2 reasons. Bits and pieces of food stuff can fall into hard to clean places, attracting pests like cockroaches and ants. Also the aroma from the food which is so pleasant when you are eating, becomes a disgusting stench inside a confined air-con place.
The rules are there for a reason, and this was one of those that had been rather good, not a perfect rule, but helps making MRT rides a little more tolerable for everyone.
You were being a total a55 for eating in MRT, shame on you!