I'm not familiar with the canon myself, but it's pretty clear that the workers aren't watching you at all.
With one glaringly obvious exception, they have sight radius 2; as long as you don't hit them and stay beyond their sight range, you won't exist for them.
And, until XP for killing aliens is finally purged, they have the absolute worst shots/XP ratio for obvious reasons. I don't mind taking one out as collateral damage from a krak grenade, but other than that it's usually better to outrun them than to kill them even if they do notice you.