If I understand your question correctly, every time the loop runs, you want to decrease “powerlevel” by a random value, then display a message depending on whether powerlevel can be reduced.
Here are two approaches.
1) use an if statement in your for loop
for (conditions){
if(powerlevel cannot be decremented){
//display a messsage
break;
}
// display a message
}
conditions could be iterating through all the experiments
2) use a while loop which checks whether powerlevel can be reduced in every loop
while(powerlevel can be decreased){
//display a message containing the experiment number (starting at 1)
}
//display a different message