I encountered a noise from a Zombie but I couldn´t see him. In order to see him, I used the rest position to see that he spawned under the buidling (I think it was near to Berezino). By trying to reconstruct this and maybe glitching through the wall, I couldn´t move. I wasn´t even in the rest position. My Character was stucked in the crouch position but I wasn´t able to change that. A Respawn helped by the way.