It's not true that the oil will always pass through you that fast.
Sometimes you can absorb it like a meal. But in either case don't worry, what's important is just to drink the oil so that you stimulate the gallbladder contractions.
I am pressing now to revise the recipe from epsom salts (bad), and magnesium citrate (slightly better), to magnesium glycinate (best).
Also I see that a lot of people are doing daytime flushes, which I agree is a lot better than night time.