The duel in Deadline Gulch is readable on purpose. You can see it coming before it fires, and if the sound is on you hear it first.
This is unusual. Most slots reveal a feature at the moment it triggers, because a surprise is cheap to build and reliably produces a reaction.
The problem with a surprise is that it happens to you. Anticipation happens *with* you.
We prototyped four telegraph lengths. Too short and there is no tension to build. Too long and players stopped believing it was coming at all. The number we landed on was the number in every single playtest group.
The audio cue arrives roughly 180ms before the visual one. That gap is not a bug. It is the reason the feature works.