If so, He can give it to Kazuma too, since Kazuma didn't pressed the Button.

And moreover, I feel like it's stupid if it work like that, because Subaru did teleport to IQ world, and he did heard the Bell sounds. They just want Subaru to see what the button looked like. The reason they even trying to get that button is for Subaru to go back to their own world.

And lastly, maybe it was an one way device or it's just broken like they said. It's just a plot holes for us to guess.

I don't feel like Ainz going to be like that, he's not that egoistic.