this is in response to the bomb in hat of mcallister theory

if u see the chart rigsby is point towards (arround 7.12 min in the episode) see image below
http://nl.tinypic.com/view.php?pic=s5l2dt&s=5#.UozLj8S4V8E

the origin of the bomb is in the middle of the room

and since mcallister left his hat on the couch when walked towards betram and reed... the bomb couldnt be in the hat.  the couch was leaning against the wall

that means... something else created the explosion... and if i remember the scene correctly... in the middle of the room stood a table  jane was leaning against.

any thoughts?