No Internet connections. Walls are made out of steel so that no signals leak out. The door would not look out of place on a bank vault. There are also a lot of restrictions concerning what you can do with these machines as well. Transferring data from one of these machines to the outside world is not allowed.
Data comes in, but nothing goes out.
So the government has opted for maximum protection at the cost of convenience and flexibility. Given the fact that the data on these machines could cost lots of lives if it got out, that's a good choice. Security is a balancing act. But their attitudes are changing. It will be interesting to see how Microsoft responds to this security problem and what happens to people's security awareness as time goes on.