As per the ff: dialogue between Kounen and Blade in the film, Blade II:
KOUNEN: But fortunately for us, he doesn't know this location.
BLADE: Now... he does.
Kounen was talking about Nomak in his line above. The above dialogue was followed by a scene of Nomak attacking the vampires' security forces in the supposedly secret location where Blade was being held.
How did Nomak learn about the supposedly secret location where Blade was being held? Was Blade at some point able to communicate or let Nomak know about the location?