How do I get the "Ethically Questionable" achievement in Black Mesa?
The Ethically Questionable achievement comprises of the following actions and occur during the 'Questionably Ethical' chapter;
- Killing an alien grunt with poisonous gas
- Using the tesla discharge on the bullsquid
- Using poisonous gas on the headcrabs in their habitat
- Shooting the headcrabs with a laser
- Firing the snark cannon until it breaks
As mentioned by PWhite these are all segmented off in their own separate rooms where you're generally presented with a button to press to activate lasers.