True/False Triggers with Random Variables?

Your problem isn't a variable problem, it is a timing problem.  The answer is here:

when the man finishes moving to the correct square.

How do you know the man has finished moving? Is it a motion path that moves him? Is it an intercept? Whatever it is, that is the timing to put in your trigger to initiate showing the question. Variables seem unlikely candidates to help, as they are merely sticky notes that keep track of a condition. You could use them like "Show question 17 if man is on square 17 ([locationVariable = 17] when motion path 3 ends"

For more definitive help, attach your .story file here.