Good point. We argue (and I believe) that "baptism" means immersion. But it did not mean immersion on many occasions in Scrioture (in fact, I am not sure we can point to one occasion where it without does...we take it from the exact meaning of a word, which is a method we often reject in other instances).
Shall we gather at the river, seems to have been a baptismal hymn... And as one of our preachers have said if the candidate is not regenerated before they are immersed in the liquid grave they go in a dry devil and come out a wet one... My previous pastor long gone to be with the Lord, didn't let any water hinder him... He was baptized in the Pacific Ocean in San Diego, California... We just couldn't get the Coast Guard out of him... You hear me Squire?... Brother Glen
Btw... I was baptized in the church baptistry!