According to O'Brien, what makes a martyr? Why are there no martyrs in the Ministry of Love?

According to
, martyrs are created when men are
killed out in the open while they are still unrepentant. 
Because they are
dying because they will not abandon their true beliefs, their death is
glorious
and later in history others take up their cause.  The Ministry of
Love makes sure there are no
martyrs in two ways.  First of all, their
brainwashing is so complete that "all the
confessions that are uttered...are
true...(they) make them true".  The confessors have had
their minds altered
to the point that they truly believe that
"two-plus-two-equals-five"; they
are emptied of themselves and filled instead with the
Party and Big Brother. 
Secondly, they are "lifted clean out from the stream of
history".  The basis
of the Party's method is to literally rewrite history.  Since the
Party
controlls the media, and, for all intents and purposes, memory, in their altered
version
of the truth, no one will know about men who have been martyred
because there will be no record
of them ever having
existed.