Even large Styx missile leaves only less than 10 feet wide entry hole. The Neptune's one would be like 3 feet. It exploded inside. Everyone inside that superstructure died.
also: remember that [on the photos circulating on the internet] she is already ~3 meters deeper in the water comapared to the time of the [alleged] hit. Any huge hole next to the waterline would already be underwater and thus not visible.