The SIRENS which sound around campus when there has been a Tornado Warning are not for alerting people who are already inside. This is official Purdue information from the official Purdue people who know the official answer.
Purdue University Severe Weather Policies.
|Month||Average # of tornadoes, 1950-1999|
And you might next wonder HOW AM I SUPPOSED TO KNOW THERE'S A TORNADO WARNING THEN? (Read some of those policies above, and stay tuned...)