I just sounds like, ie, "sacrificed himself", that he more or less committed suicide in OS2 - it was "stabbed in the back" prior.
Mayhap it is a case of one faked death followed by a back stabbing. There are quite a few years between the two games after all, so for both events to have happened (considering the deaths themselves are very different... after all he ended up in the Hall of Echoes in DKS).
