If the Rams win the division, the Lions would play them at Los Angeles if the Lions win the division. We get to boo the Stafford children in another city. We can also get a Goff chant going in their stadium.
I think he would be more likely to go with Ben Johnson. If Glenn gets a job with the Saints, he probably sticks with the Lions. Better chance for a Super Bowl and a future head coaching job.
I just saw that Josh Allen is pretty bad vs. pressure. 39% completion and about a 50 QB rating. Goff, meanwhile, has been one of the better QBs vs. pressure this year, but the narrative would be reversed regarding these QBs.
Once it goes past the line of scrimmage, it's essentially treated as a punt. If no one touches it, it's Dallas's ball wherever it lands. Since a Dallas player touched it, it's a live ball like it would be on a muffed punt.