[Ynought]

Yes, to the best of my knowledge, in general light beams following the curvature of space-time are reversible so that you would be correct for everything EXCEPT for the special case of black holes.

In the case of black holes, the escape velocity of the black hole is simply too great to allow light to escape at it's velocity if it originates from within the event horizon.

It would be like if you were rolling tennis balls to a friend across a trampoline. If you place a bowling ball in the middle of the trampoline, suddenly rolling the balls straight to your friend won't work anymore, because you need to roll them angled to account for the bowling ball in the middle of the trampoline causing the trampoline to be bent a bit so the balls will curve around the bowling ball and a person on the other side of the trampoline can then grab them and roll them back to you with the exact same speed and angle that you rolled them to that person.

However, if you tried to roll a tennis ball instead from the MIDDLE of the trampoline (where the bowling ball is) to your friend you would find that no matter what angle you chose you could not get the tennis ball out if you used the same speed to roll it as before. On the other hand, your friend will of course have no problem rolling tennis balls from the side of the trampoline inward to you.

This is the situation you find light in. Because the absolute maximum velocity that ANYTHING including light can have in a vacuum is equal to c if the black hole is bending the trampoline of space time so much that that velocity doesn't surpass the curvature then it doesn't matter what angle the light faces, it's just going to end up heading right back towards the black hole.