Nice review! Thanks!
Actually, when the guards say "huh?" that's the warning, but of course without a learn sounds feature you wouldn't know that without trial and error... Also I think the problem with guard footsteps is that when there are two of them the audio ends up syncing perfectly and causing the positioning to sound off, so a delay between them would be helpful.
You may be interested to know that the egg break consists mainly of well, an egg cracking, but also a pepper being broken and a tomato being crushed, along with a designed bone crack and zombie bite.