The particle []or[] antiparticle (only one avoids falling in) produced usually does pair up and annihilate with another (anti)particle, but that happens above t

The particle []or[] antiparticle (only one avoids falling in) produced usually does pair up and annihilate with another (anti)particle, but that happens above the event horizon, so the photon resulting from that annihilation sometimes is pointed away from black hole and escapes. It's only very small black holes where the pair-production particles themselves have sufficient height and speed to escape.