There are 5 cards left in the deck, and 1 clue available. The only clued cards are Alice's 5s.
What action should Alice perform?
It might be tempting for Alice to clue red to Cathy, which would be a Finesse on the red 4. However, doing so would risk losing the game.
This is because it is possible that Alice will draw the blue 5 and the purple 5. If she did, then she would have to play 4 cards in total. If Alice clues on this turn, then it would be impossible to play all 4 cards (because the game will end).
Instead, it is correct for Alice to play yellow 5 or green 5, letting Bob save the red 5, and Cathy getting the red 4.