I was wondering about a scene in *The World's End*. Why did Andy drink those shots in the "Cross Hands" Pub since he's supposed to be teetotal?

I have my theories but feel free to post your own.

1. He feels pressured by the fact that the others want him to drive.
2. He's craving for alcohol ;) (come on 16 years!?)
3. He prefers Steven's plan 
4. He secretly likes a waitress in "The Good Companion"
5. Just because the plot needs him to...