2003 GMC ENVOY XL 370 Structurebody Problems

MY WIFE WAS IN THE PROCESS OF CLOSING THE REAR HATCH ON OUR 2003 ENVOY XL (80,000 MILES) AFTER REMOVING SOME ARTICLES FROM THE BACK. SHE HAD MOVED THE DOOR ABOUT 1-2 INCHES DOWNWARD USING THE MOLDED HANDLE ON THE BOTTOM OF THE LIFT GATE TO CLOSE THE DOOR WHEN THE REAR GLASS SHATTERED OVER HER HEAD. LUCKILY SHE WAS NOT INJURED BUT WAS COVERED IN SAFETY GLASS. THE GLASS WAS NOT DAMAGED YESTERDAY WHEN I DROVE THE VEHICLE AND UNLOADED SUITCASES FROM THE REAR. AMBIENT TEMPERATURE WAS ABOUT 70 DEGREES. I DID NOTICE THAT THE REAR BRAKE LIGHT ASSEMBLY IS NOW ANGLED UPWARDS IN THE 'GATE RAISED' POSITION, EVEN AFTER CLOSING THE HATCH. ALSO NOTICED THE TOP, RIGHT SIDE RUBBER GROMMET ON THE STAMPED BRACKET ATTACHING THE GLASS IS VERY WORN, ALLOWING SIGNIFICANT MOVEMENT. I PLAN ON TAKING THE VEHICLE TO A DEALER TO DETERMINE ROOT CAUSE IF POSSIBLE...