Hey, we just had the same question come up in our game. Dont know if you were watching the twitch stream when we were talking about it.
The room in question is Area 16 : Chamber of Statues in Keep on the Shadowfell which is down on the second level of the keep. Here's the stat blocks for the baddies :
Dont mind the crummy MS Paint cropping job. I searched around online and didnt find too much from googling various keywords (though I did find several pages complaining about how broken this fight is and how it should be better planned out) so I figured I'd start sifting through both the KotS quick start rules and the Dungeon Master's Guide and finally came upon the answer...I think.
Quote:
Dungeon Masters Guide : Page 66
Damaging Objects
Like characters, objects have hit points and defense scores (except for Will defense; see Object Immunities and Vulnerabilities, below).
An object’s AC, Fortitude, and Reflex defense depend entirely on its size. (As you can tell from the following table, it’s pretty easy to hit an object; so easy, in fact, that many DMs just skip the attack roll unless the situation is particularly dramatic.) An object’s hit point total generally depends on two factors: its size and its material. As a rule, larger or thicker objects have more hit points than smaller or thinner ones. Objects made of stone or metal have more hit points than those made of wood or glass.
Exceptions to this general rule abound. An object that’s big but full of delicate moving parts might have fewer hit points than a smaller, more solid object, because it doesn't take as much damage to render that object functionally useless.
Object Immunities and Vulnerabilities
Usually, it doesn’t matter what kind of attack you make against an object: Damage is damage. However, there are a few exceptions.
All objects are immune to poison damage, psychic damage, and necrotic damage.
Objects don’t have a Will defense and are immune to attacks that target Will defense. Some unusual materials might be particularly resistant to some or all kinds of damage. In addition, you might rule that some kinds of damage are particularly effective against certain objects and grant the object vulnerability to that damage type. For example, a gauzy curtain or a pile of dry papers might have vulnerability 5 to fire because any spark is likely to destroy it.
Damaging Objects
Like characters, objects have hit points and defense scores (except for Will defense; see Object Immunities and Vulnerabilities, below).
An object’s AC, Fortitude, and Reflex defense depend entirely on its size. (As you can tell from the following table, it’s pretty easy to hit an object; so easy, in fact, that many DMs just skip the attack roll unless the situation is particularly dramatic.) An object’s hit point total generally depends on two factors: its size and its material. As a rule, larger or thicker objects have more hit points than smaller or thinner ones. Objects made of stone or metal have more hit points than those made of wood or glass.
Exceptions to this general rule abound. An object that’s big but full of delicate moving parts might have fewer hit points than a smaller, more solid object, because it doesn't take as much damage to render that object functionally useless.
Object Immunities and Vulnerabilities
Usually, it doesn’t matter what kind of attack you make against an object: Damage is damage. However, there are a few exceptions.
All objects are immune to poison damage, psychic damage, and necrotic damage.
Objects don’t have a Will defense and are immune to attacks that target Will defense. Some unusual materials might be particularly resistant to some or all kinds of damage. In addition, you might rule that some kinds of damage are particularly effective against certain objects and grant the object vulnerability to that damage type. For example, a gauzy curtain or a pile of dry papers might have vulnerability 5 to fire because any spark is likely to destroy it.
This leads me to believe that the bad guys that have a dash rather than a defense simply cannot be attacked at all by attacks that versus that defense. I cannot however answer why statues have a reflex.