Sort of about halfway back...more or less...and not on the far left or right.

By the way, the best answer to being bothered by the intrusive activities of other audience members (and it's the main problem one has at movies, I find) is this: go at the times of least attendance if you can. You will be sitting in a virtually empty theatre. This is easy if, like me, you're self-employed. It's not so easy if you're on the 9-5 workweek.