This might be far fetched but I think Nicholas fell on him and the walkers are eating him. With the blood and guts being on Glenn the walkers will leave him alone and he can escape. That might be wishful thinking though.

He might come back as a walker and make it to Alexandria and Maggie will be the one to find him and kill him then she will find out later that she's pregnant.

Idk what Darryl was trying to do either. I think that the rv will start up right before the herd gets to Rick. Do you think Rick was cut or bit?