If this is so, the first body recovered was the last to enter the tunnel, that is Mauro the Instructor, the second body was of his assistant ( I read somewhere that he dived with double tanks so it's presumed the others dived singles) the body still missing is of Silvio who was on holiday but goes there every year and knows the area well. So could it be that narcosis made Silvio decide to enter the tunnel and the others decided to follow? I feel we will never know what really happened, but in Palinuro it is normal to take tourists into the grottos, probably most are caverns, everything goes ok for thousands of times, then someone makes a mistake...........