The reaction of the other players at the table while the scene plays out is telling. It appears that no one expected this storyline to go where it went.
Yet, nobody said "I don't like where this is going."
To be clear: I don't blame them for not saying it. Probably, I probably would have been quiet in that situation too. I believe that safety/communication tools are usually not necessary but in rare cases they are. Thus, it is a good practice in general and worth some overhead.
As someone who is on board with people using communication tools:
Do you think people who would not say "I don't like where this is going" would be willing to tap the traffic lights? It's basically still you saying "I don't like where this is going", still in full view of everyone. I'm honestly not sure how the communication tools help with speaking up, besides providing a few predefined options for you ("yellow light means this, red means this") instead of you having to find the words to explain how uncomfortable you are and what you want the solution to be. I'm not trying to tear them down, I'm just honestly curious.
Might as well out myself and say I've never personally needed to use these. But I don't have to fully comprehend them to support other people doing what makes things healthier and easier for themselves, hence my not understanding while still supporting people using it.
It strikes me that this could be quite useful when used proactively.
E.g. - Player Character Byrnwolf just got a crit on the Bandit Lord with his Greataxe. Queue the GM: "How comfortable would everybody be with a description of Byrnwolf splitting this guy in half?" All the players tap red, yellow, or green in response, and the GM can moderate from there.
It would be good at providing ongoing feedback for the GM to guide their style over time.