I tried toying with it, and it really matters the lighting in your room. my room is very bright right now, but if I turn off the lights, things really change.
here is what I tried, I cut out the body, I then increased the black levels of the main image so that the area where the body was looks black, so that it doesn't look like the area is well lit so it shouldn't look like the character with the flashlight should see the body, I then added the body back in (no changes) so that the body stands out a bit. It kinda worked, kinda like a ghost effect, where you see their body in the darkness, but it still wasn't readable.
to make a body readable, the silhouette is the most important, it is why taping bags to your body (a military tactic) is a good way to camouflage, because you distort the human shape (shape is how the human brain identify things from a distance, ie most characters look the same in video games because they may all have the same base head shape). So we need to see the shape of their body. Now I couldn't do this well with the images, but here is a suggestion. Could you render the body separate?
Mainly, having different lighting from the body. Because most of the light is being diffused and reflected by the white doors, in order to make the body viewable this large white diffused area makes a very soft lighting of the body, thus it is quite evenly light, and this makes it look so obvious to find. Instead what you can try is, when you render the body, instead of being indirectly lit by the scene (light bouncing off the doors) use a fake light instead, a smaller (physically small point light) about where the door is. The reason for lighting it with a small light is to make the light less soft so as to only light up the side of the body (the outline) and not fully illuminate the body, so the shadow (around the body) becomes crisper (can make a fake feeling), thus the body is less illuminated, it is hidden by the shadows/darkness, but because what lighting there still is available, it is directed to illuminating the side (outline) of the body, thus you can still tell there is a body there but you struggle to see who or what it is).
We can improve this effect, push the light farther away from the camera. Why? Well the idea is, as the light goes far away from the camera, in order to reach the body, instead of lighting the body from the side (where the doors are) the body lights it from behind. so the light becomes more of a glancing blow before it reaches the camera, and is more concentrated on outline the body, improving the effect. If you were to do a 3 point or 4 point lighting setup, this is called the rim light.
