Full disclosure: I probably don't know what I'm talking about. And I don't think I'm in a position to make any inferences. But I do think I can feebly offer another example:
Consider an aspect of your consciousness that is taken for granted nearly every moment of every awake and visually enabled person: the boundary at your extreme peripheral between what you can see and what you cannot see. Specifically, that distinct or wuzzy line that you should see when focusing on what should be the area where the angle of incoming photons do not enter your eye.
I've tried relentlessly to "see" this line--to perceive or experience it in a sense. But there is some aspect of my cognition preventing this qualia event. Somehow or way, before sight is reaching my conscious "thread" the visual input is being parsed and interpreted.
Backing away from that boundary, a non-trivial amount of visual qualia begins and increases as the angle to your pupil approaches 90 degrees, with the most information coming from directly in front of your focus.
Now, in a very real sense, towards the boundary point where there is a small but non-zero amount of information being delivered to your eye, a part of your mental process is dealing with that information. If your eyes are open, you cannot help it. If energy hits the nerves at the back of your eye, that energy will be dealt with (excluding any transmission loss).
In almost all moments, this information at the boundary is parsed in some way by some mental functions. (This is purely speculative neuroscience, but I would imagine that the small but non-zero amount of information is enough to trigger initial neuron interactions, but not enough to propagate into the network of neurons that constitutes our conscious thread--much like a raindrop could hit the ground of a riverbank but be absorbed by the ground before reaching the flow of the river.)
That is, unless there is something "signifiant" at or peripheral. Like a very bright light, or something like it, that would alert our consciousness to attention. I'd be interested to read studies about this that would specifically limit the overflow to other senses or angle of light, but let's take these as occurrences as particulars. (Again, if I put on my speculative lay neuroscientist hat on, I'd imagine that there are pattern recognizing systems early on in the process that increase the intensity of the message when non-matching patterns are inputed.)
Moving more towards the center of focus, there is more information to parse. At about 60 degrees out of focus, there is an experienceable amount of information. If something moves, I can sense it. But when I'm not focusing my consciousness there and nothing is moving, that mental "thread" which monitors the input of that area continues in some fashion under my conscious thread.
Thus, there is a mental process which is parsing visual information not in focus which everyone experiences and for the most part there are a significant amount of moments that we are not ware of them. This gets us a step closer to events that no one is aware of, but not all the way there.