Why would you take it on an iPad? Do you not have a computer of your own?
I had a couple students who could not afford a computer of their own and felt that public computer labs were a bad place to take practice tests. While frowned upon by retailers (not illegal), I think they both opted to carefully look into return policies. If you are really careful, you might be able to find a policy where you can buy a computer, take excellent care of it and the packaging, then return it for a full refund (after taking several practice tests on it)*. Later on, one of them mentioned her problem to her professors and lab PI and someone lent her a laptop.
It would be nice if everyone had a fully functional computer, but some people are too poor.
*Out of all the ways return policies are used and misused (to mine bitcoins, etc.), I think that using one to get into medical school is one of the most innocent most respectful kinds of potential misuse. It is also a very gray area where you will be buying a computer for college later on, and whichever computer you try out now might be a candidate for purchase down the line. <--- In that sense, you're arguably NOT misusing the policy. I know so many well-to-do people who buy all kinds of stuff and if it doesn't perform 100% perfectly or if they just change their minds and don't want it anymore, it gets returned.