I am quite familiar with Torrents. Pausing in the middle will not affect your download at all. Switching your connection might only affect how fast you download.
The way torrents work is every file is broken down into pieces. How many pieces depends on the file size. UTorrent will download different "pieces" of your file. Which could be from different people. It is shared amongst all the people still downloading (sharing pieces that their Torrent prigram has already downloaded) or people that are seeding. Meaning they have completely finished downloading the program and are sharing every piece for others.
What I like about torrents, is if something happens like your internet cuts out, you won't have to restart your download from the beginning again. When your internet comes back, your Torrent program will continue downloading the pieces it started downloading. Or depending on the availability of other pieces it might start elsewhere.