I can see the point of short code phrases being useful to communicate to all staff that they need to instigate certain actions but unless they have an innocuous meaning to passengers they are bound to cause panic to passengers with a resultant risk of panic, stress and associated unpredictable behaviour.
Surely the senior cabin crew would already be on their way to the flight deck having heard the loud bangs and been alerted by the passengers reaction to the sheets of flame!
I think any ordinary passenger would find the use of blatant code words rather disconcerting and would be worried about what they are hiding. I also think that any codes involving types of snake or any other colour apart from green are probably only suitable for military use, although to be fair it has been pointed out that the actual code word was 'apparently' misheard. Perhaps the passenger had seen the film 'Snakes on a Plane' !