Basically, the equivalence principle (EP) states that if someone is in a rocket in empty space with acceleration $g$ equal to that at the surface of the earth, any experiment he does cannot distinguish whether the rocket is accelerating in that manner or the rocket is just sitting on the surface of the earth. So if he were to let go of a ball, it would fall to the floor of the rocket in either case. If he were to throw the ball horizontally, it would follow a parabolic path.
Now let's consider that the observer inside the box shines a beam of light horizontally. Because in the first case the rocket is accelerating, the light will follow a parabolic path and strike the wall at a slightly lower height. EP therefore predicts light would also follow a curved path inside the stationary rocket, i.e., gravity bends light.
But the bending will be based on the acceleration $g$, so isn't EP incorrectly predicting the Newtonian bending of light, which is one half of the value obtained using general relativity?
Let me guess at an answer: EP only holds for a "small" rocket and within that approximation the general relativity and Newtonian predictions match?