I went back and re-watched Nicolas and Glenn's death scene seven times. I am positive Glenn was getting his stomach eaten. 1) He was screaming and his facial expression held a look of agonizing pain. 2) If you pause and play, pause and play you can see a walker reaching and pulling which pulls up a little of his shirt. His shirt was tan and Nicholas was navy or some dark color. 3) On Talking Dead Scott address us, the fans, saying that we will be seeing Glenn in parts, or flashbacks or current event.