Firstly, I see no reason why it couldn't be modified to be portable. The mechanisms are all self-contained. Although it would probably be best for it to be anchored to something...more testing will need to be done.

Secondly, it's a testing apparatus itself, used to investigate all sorts of things. Problem-solving skills. Manual dexterity. How many times a test subject will rocket themselves into a wall before they figure out a way to stop rocketing themselves into a wall. Take your pick.

And finally, it's safe...enough.

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Yeah, welcome to Aperture. We created a portaling device while trying to make a shower curtain, and the woman you're currently talking to was originally created to de-ice jets. Science!!!]