Place it just after the strange setup is shown, so it acts as the comment on the reveal, then follow it with a bigger reaction. Open the moment with Sudden Suspense to build tension, and close it with Oh My God Wow once the experiment goes wrong.
Über diesen Sound
This is a short Russian voice reaction, about four seconds long, in which a speaker notes the strange experiments going on around them. The delivery is dry and puzzled, turning a simple observation into a knowing aside. It gives a listener a feeling of amused suspicion, as if something odd is happening just out of frame and everyone else is pretending it is normal.