My wife was unloading bags of groceries from the back of the vehicle. I had opened the liftgate once I pulled into the garage. One of the bags she grabbed was double bagged but one came off and went under the rear bumper. I got to the back of the car where she was at and I asked her what was the bag under the car, assuming it still had items in it. She explained it had came off the bag in her hand and she reached down to grab it. When she got it I heard the noise from the liftgate that a closure was activated via her getting the bag from under the car. It was coming down fairly quick. I told her loudly to move back, the liftgate was closing. When she did she lost her balance. She rotated around and fell in the driveway, skinning her knees and her hands and ended up on her back wondering what happened. Thankfully she did not hit her head. She is [XXX] and coordination is not a strong suit for either of us. I am [XXX]. A similar event happened to me when I had to reach something deeper into the back of the car and my foot went too far underneath the rear, activating the liftgate closure. I was able to move back without issue... INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)