No. Once you put in the Break action, it will terminate the loop. I have overlooked this and thought it was a bug. Anyway, do you have any success in the Magazine Owner of Unit function? Can't really see it in the built-in functions by Blizzard though.
I haven't used that function before, but I use while loops all the time for all sorts of things, I also have a couple infinite loops, mostly just doing some math calculations so nothing big. They don't produce any lag and I've never seen my editor crash or the game crash as a result of their use.