we have problems with the reflection captures in Unreal Engine 4. We have placed reflection capture actors in a floor (image 1) and the doors that are actually about 200 meters away are reflecting the lamps from image 1 (image 2).
You can lower the influence radius of a Sphere Reflection Capture Actor and you can adjust the Box by adjusting the Scale settings to best match the hallway you are wanting to add the box to.
To Combine a few things here, Arnage is correct that you should have more than 1 capture actor per level or reflections from the entire level will pull from that one capture actor. Also though, your bounds are outside of your walls. Capture Actors will pull information from distance sources if there is not a stopping mesh, this is how a box is rendered in a reflection even though it is not technically within the capture bounds. Try decreasing the box bounds to be inside of the walls of your hallway.
Also take a look at the reflection capture documentation which does a good job laying out how to use multiple capture actors effectively.