Zaitsev was doing something he had never done before, but now had no choice but to do - lying motionless next to a decaying corpse, making no sound, simply peering through one slightly open eye at the bushes two hundred meters away, looking for his prey or perhaps...the Grim Reaper.
He was very focused on this task, both out of habit and necessity. If he made even a slightly larger movement, or emitted a noise he shouldn't, the next second a bullet would penetrate his brain, sending him to join the deceased beside him. To avoid making such fatal errors out of hunger and anxiety, he had to concentrate all his energy.
He was being watched.
This wasn't an exaggeration or an expansion, it was a cold hard fact.