In 2001 the USA had the terrorist attack on the World Trade Center.  It has become vogue to call it the 9/11 Tragedy, as if it was a hurricane or an earthquake, but it was not.  It was an act done by men, evil men.  A few years later, both Spain and England faced similar events.  And now India.  I am not so schooled in geo-politics to try to draw strategic significance here.  All I can do is to draw operational similarities in the hope of understanding my enemy better and thus be able to defeat him.  Similarly, to be able to teach my students to defeat him.
 
Here is what we know thus far -
 
1).  The attackers were organized into buddy pairs, allowing one to shoot while the other moved, and so forth.  The buddy pair, or "Two Man Team" is a development of small unit tactics very prevalent in SWAT operations. For urban close quarters battle, where areas tend to be compartmentalized, it makes sense for each room to be "taken" by two men.  It is not hard to develop the skills of a two man team.  For example, we teach a team tactics course and after two days of instruction, attendees are quite well skilled in working through any problem as a well oiled team.   It is obvious that these terrorists had a good amount of exposure to this material.    

2).  While we don't know everything yet, it appears the two man teams operated autonomously in Mumbai.  That means that while they had an overall objective, how they achieved that was up to the individual team itself. Now we see the autonomous two-man team, well drilled, practiced, each with its own set of objectives, and apparently in contact with one another. If you think about it, this was a bigger, better planned Columbine with multiple and much better prepared shooters.

3).  Until the "elite operators" showed up later, it doesn't appear that the "armed police" did much to stop them at all. I have never been to India, but if the training and pay of their local police is anything like what I have seen in the many Third World nations I have visited, I don't expect the terrorists would have met much resistance from anyone in authority.  After all - if they give you an old Enfield with no ammo and $150 per month to live on, do you really want to jump into the lion's mouth?  
 
4).  India is a very restrictive place as far as civilian ownership of weapons, and the likelihood of anyone present being armed was slim.  Regardless, I think this is once
again indicative of how an armed civilian may have been able to stop at least one of the two man elements.  Those who wish to argue the point will be referred to the British reporter who commented that if he'd had a gun he would have killed both of the terrorists he saw (because no one else was even trying to do so!)