Blanks would certainly explain the need for the hammer he "used" on the glass... Not an expert on building glass, but most certainly tempered. But is it laminated like a windshield to prevent falls?

There was a clip from Tosh.0 in 2010 where a reporter couldn't break a vehicle's window in a junkyard: from a segment where they were trying to show how easily windows break... He hit the window several times before it let his fist thru - sending him to the ER