Because there is always a lapse for something to happen.
Last time I checked, nothing is instant. Maybe modern science will eventually prove that wrong.
Also, who says that this exploding blackhole happened before us. If it has no time, how can we place it chronologically? That's like saying something with no height, is shorter than you. It doesn't exist in all of the dimensions you do, and so you are restricted on your ability to compare it to you.