People disappear here on a regular basis. It would not do for that to happen and no one notice. You could either be sent back home to your universe, or kidnapped by the Malnosso to be subjected to various forms of experimentation.

[Spock didn't know how detailed he should get in that...]

The Dome is a building with holographic technology. It is utilized for training simulations and other activities. I myself spend much time there programming different simulations for private or public use.