Seeing in the dark

My apologies for not posting in a while.
Here's a neat little fact about dogs' vision.
Their sight is as bad as ours in the dark, with one big exception.
Dogs can see movement in the dark. What I've heard is that movement in the dark appears to them in a glowish, night-vision-like form. Think cats.
Not that I've done any scientific research on this, unless you count my experience with Sensi as scientific.
Here's what happens:
We have a long, dark hallway. At the end of the night, I turn the lights out and walk down the dark abyss to the bedroom (I figure, why turn a light on? I ought to learn how to navigate my own house in the dark).
Sensi always knows when it's time for bed. He hops down groggily from the couch and plods along behind me.
As long as he's made it to the hallway at the same time I have, he has no problem following me as I walk down the hallway. But then, when I reach the bedroom and open the door, it's another story.
I stand there with the door open, waiting for him to enter the room so I can close the door behind us.
Only, he stands there in the hallway, not moving. Why? Because my movement has stopped and he can't see anything.
Many times, I assume he's walked past me into the bedroom and close the door. Usually, I hear his nails on the wood floors backing up as the door (now moving toward him, so he can see something) swings shut.
Realizing this is what's happening, I now flick the hallway light on for a second so he can see to walk into the room.
Then it's my turn to bumble around in the darkness, trying to find my way to the bed.