"Stop" and "drop" are completely unnecessary.
If I catch fire, do I really need to be told to stop doing whatever I was doing before? A pancake recipe would not tell me to stop doing what I was doing before making pancakes. Stop, make pancakes, eat.
And doesn't rolling straight up IMPLY dropping to the ground? I can't levitate. I'm not going to be rolling midair. I'm not a fighter jet.
So really the advice I should have been given is:
Roll.
If you are on fire:
Roll.