Sometimes, the green turn-left light doesn’t make itself known until it starts blinking. In this case, a black Mercedes honked a white Lancer in the final moments before both cars zipped off into the night. I’ve driven down this road by Yishun MRT countless times, and such occurrences are common: Drivers consistently miss the left turn light and get honked at by others.
So, what is the morale of the story? When waiting at a left-turn only lane, get ready to turn left when you can turn left, and when it is safe for you to turn left, and especially when someone is waiting behind you, and also when you took that lane to turn left anyway.
Turn left.