Just curious, since the americans had initiative and moved first couldn't the panther op fire and then move so that the US inf are no longer adjacent? If so it seems as though it is best to close assualt during enemies initiative so that the Panther has already moved. Also if the US units are in the open I'm guessing the panther could move into one of their squares and initiate a raiding attack (overrun)?
This is all exactly right. It was just meant as an example showing infantry in position to do an assault. The panther definitely has options. It is probably better to close assault when you do not have initiative (or close assault an immobilized tank). The Panther would be able to move and escape the planned assault or even initiate a raid attack on any infantry in the open. Often it's best to move last.
It's also probably best as infantry to raid a tile (not close assault) when you have initiative. This way, during the combat phase when that second attack rolls around, you can get execute it first.