By "bar" I mean "door", and by "walk into" I mean "stand in front of".
They try the knob, but it's locked. There is a weather strip at the bottom so they can't see in at all. The scientist sets about tapping on the door and attempting to move it around in its frame.
Meanwhile the atheist and theist begin to argue.
"What wonderful thing musts be in this room."
"Of course it's not empty. Why would someone lock an empty room? Why would there be a room for nothing in it? No, it is logical that there would be something in there."
"We had no proof at all of anything in there. It's illogical to assume anything at all, especially that the imaginary items are 'wonderful'".
"You're just being blind. The room is clearly there. It is clearly artificial. It must have a purpose."
"It must have been built. We cannot assume it has a purpose. We definitely cannot assume that purpose is to store 'wonderful things'".
"You're being ridiculous, you cannot even see inside. Anything could be in there!"
"Also, nothing could be in there."
At this point the scientist is thoroughly annoyed with their attempts at philosophy based on poor logic and zero evidence. Thankfully, he carries a gun for these situations, but with one bullet; he's almost a pacifist, but not quite. But what should he do with it? He sees only one way to silence both of them.
He shoots the door, blasting a small hole in it.
Immediately the two combatants switch to physical methods, shoving each other to try to peer inside. It's a small hole and they block the light every time they look, not that they can concentrate, since they keep pushing each other away before they can focus on the dim conditions. But they are at least certain of one thing: the room is dark.
Finally the atheist has come to the conclusion he already had.
"See, I told you it's empty!"
"But it's dark, it could be in that shadow right there."
"The entire room is shadows!"
"Exactly, just imagine all the wonderful things!"
The scientist wanders off to ponder uncertainty and whether a coin flip would determine if God plays dice, musing that the true answer to Schrödinger's cat was to think inside the box.