This exactly what HBO wanted...EVERYBODY is talking about the ending and will forever!
We will each put forth our own scenario:
Mine is the guy in the bathroom comes out with a gun like Godfather...but the guy with the hat is FBI undercover sent there by Tony's FBI connection and he shoots the gunman before he wacks Tony. The FBI doesn't want Tony killed...they want him in jail. Tony's FBI guy heard the wiretaps of the plan to kill Tony and he interceded. he felt he owed him one for the terrorist tip. IMO
