Quote Originally Posted by ramanth

... though, why were the police opening doors?
Wouldn't they just set off the fire alarm to get people out?
Or go door to door and knock and if there was no answer, move on?
Couple reasons:

1) To be sure the occupant isn't disabled and unable to call out or flee ...
or
2) The "empty room" MAY be the one with the bomb!

In fire and bomb situations, someone needs to visually check ALL rooms or
areas where a person could be either trapped or hiding, or a "device" could be hidden.

/s/ Phred