Editor's note: With this SWAT blog, we're answering a question proposed in the May 29 blog, "Campus IED Attack: What Would You Do?"  You may want to re-read it now before continuing. You told us how you would handle the scenario of a campus active shooter suspect with IEDs. Here's the answer:

With the scenario presented, you face two types of threats—immediate and imminent. Your task is to prioritize your responses and save lives.

You've heard the explosions. The pressure cooker in the library is a possible IED, and you've got reports of two shooters and a possible vehicle-borne IED (VBIED) parked in the street. As is the nature of these events, you'll be presented with numerous other distractions.  The injured and wounded are always a concern.

You've taken command, but you'll have to deal with other commanders who aren't at the scene giving counter-productive orders and instructions. To take care of business and complete the mission, you'll have to get past the clutter, drive down range, and get it done.

The shooter engages your team in the library, presenting the first obvious, immediate threat.  He needs to be neutralized now. Is the pressure-cooker device on the library counter an immediate threat? Possibly, but it's more likely imminent.  Should your team enter the library in the face of imminent dangers? If that and other unknowns stop you, we can assume the worst for the six innocents we know are still alive in the library. What if the IEDs are armed and ready to blow? What if the other shooter has taken up an ambush position? If we think for too long, we can sometimes "what if" the innocents to death.  Imminent is pending, but it's still in the future.

Now that you've put down both shooter bombers and located the innocents in the library, your next course of action should be clear. Get out, now! If there's another route out of the library and away from the suspected IED, find it and use it. There's no guarantee your alternate egress is safe either, but you're getting away from a known danger. Remember to use distance and shielding when dealing with IEDs. You just might want to avoid exiting the building on the side where the 20-foot box truck is parked.

Mistakes will be made when you're making quick decisions on the fly, so don't expect a perfect plan. Not even close. Perfect plans fall apart on first contact.  Remember to "think long, think wrong." Alert other personnel to stay out of the school. Seal off the area, and call in the bomb response personnel.

You may encounter phony IEDs at crime scenes. I was involved in a bank robbery investigation where the suspect used several, well-constructed, bogus IEDs in the bank. It slowed the investigation at the crime scene by several hours. He also planted phony devices at a gasoline tank farm several miles away to divert the attention of law enforcement resources during the robbery. Of course, we can't take a chance that the IEDs are phony. Nor can we let devices stop us from saving innocent lives.

The suspects in the Boston Marathon bombing murdered MIT Police Officer Sean Collier , a 27-year old who had barely started his law enforcement career. He was truly one of the good guys. Let's not forget him.

Bob Parker is the Patrol Section chair for the National Tactical Officers Association (NTOA).