From S03E04, there's this 1 second Kaiji reference/similarity where Miko Iino's face goes nobuyuki Fukumoto-style and either Miko or the narrator or some sound effect whatever says 'zawa (ざわ)'.
Source: Reddit user LouijaBoard.
Afaik, ざわ is a Japanese onomatopoeia meaning uneasy atmosphere (also see here) or a Japanese onomatopoeia for like unnerving or whispering or something.
Context of scene: The narrator says prior that
To gain even one extra minute of studying time would be a windfall for Iino!
What the narrator says is understandable, and it is understandable Miko would be ecstatic over such an extra minute, but...
Question: Why the ざわ, and why is the ざわ translated to 'ecstasy' ?