Why?
Large pieces of glass obviously fell toward the ground.
Why didn't someone notice this?
Somebody did
Let the blood dry
I went to GoogleEarth and found out why: A large porch-like roof extends away from the window area around the second floor. The glass chunks would have to sail away from the wall a pretty good distance before they’d clear the low roof and impact the ground.
https://www.google.com/maps/@36.0921158,-115.1745392,299m/data=!3m1!1e3