Note: A few details were changed in order to protect the identities of the people involved.

The room was relatively empty. Just the staircase for the player to walk down from, the chandelier and the locked exit door for the player to escape from once the enemy is taken care of.
Once the chains are shoot by the player the chandelier will fall from the ceiling and crush the enemy. This is the only way for the player to move forward to the end of the level.
It was now my turn to give the level a try. I played through the first few rooms with no issues. I finally got to the last room and I fired straight at the chandelier....and it just swung around the ceiling. I fired at it over and over again and it just kept swinging in place. It finally just shot off the ceiling and flew into a corner of the room.
Time to run the numbers. If I shot at the chandelier ten times, and it fell on target twice that would mean there would be an 80% chance of it going wrong.
So think of it like this, if you were to knock an apple off of a tree using a rock, would you be able to make it land exactly where you wanted every time? There are so many things you would have to factor in when you through that rock, not to mention that once you hit that apple you would have no control over how fast or where it would fall. You can not predict the course it would take.

When you have a condition such as "Enemy can only be defeated by the falling chandelier" and "Chandelier will work properly some of the time". You really see a fundamental problem forming, and you don't even have to be a game designer to see that.
"Nope." - Unknown Game Designer
@Dannylv100