Why is this not 'lúc ngay lập tức'?
As it has the same translation with or without the được, im having trouble understanding what passivity is
No, if the "được" is omitted, the sentence become: "Nó đã làm gần như ngay lập tức", which means "He/she/it did it almost immediately".
I am suffering from distinguishing the difference between bị and được. Does anyone have a good explanation?
Được is used for something positive and bị for negative. It would be so much better if simple grammar rules like this were explained before lessons instead of making you stumble through until you rediscover the wheel.