Originally Posted by GUWonder

And as the BRU attackers may have done, they caused an explosion at one area and then a bit later hit another area that could be and was used as an entry/exit to escape the area.

Bottlenecks and herd creations make it more easy for criminals and nutcases to attack as if shooting into a barrel full of targets. But the security forces at airports that have these kind of major bottlenecks and herd pens in many places are de facto protecting physical infrastructure more than human lives whether they know it or not.