I don't associate thumb with emergency per se, I would appreciate getting thumb-thumb-thumb to make it really clear you are in deep trouble to be honest. Thumb is just a higher gear that strips out all the extras off from exit and makes me more alert. Usually, with regular buddy we'd turn and a thumb-explanation would come very soon (eg I am cold/drysuit leaky). In most cases, could have as well twirled and explained but the thumb just established right away that no cameras are pulled out, no detouring, let's just head for the first stop and get out. I think the recent JB accident was a good example from buddy's perspective why it's good to know why to just obey the thumb in some cases.

I do not like having million different signs but I do like to be in the know if unexpected decisions are made, so thumb and twirly work. If there really was an emergency with thumb we get going with the right attitude right away.