The simple sentence of "DO or die" is "In the event of not doing, you will die". EXPLANATION: Do or Die is a compound sentence. There are two clauses and one conjunction.

What is a sentence for do or die?

He was in a do-or-die situation to the bitter end. I am working hard to defeat my competitor and to win I have to do or die. When I was lost in desert, it was a do or die situation for me to survive.

Do or die compound to simple sentence?

In the sentence, there are two clauses and one conjunction. One main clause is Do and the other is Die and or is the conjunction. To change a compound sentence to a simple sentence, often phrase is added. Thus, the correct sentence will be - In the event of not doing, you will die.