The word שוטר means only a police officer or a policeman. An officer (like in the army) is קצין, a guard is שומר.
There are two types of accents. Sfaradi and Ashkenazi. The latter is common in Jerushalem and the former in most of the rest of the country, such as Tel-Aviv. You are exposed to both. With the sfaradí accent the r is said a lot like Spanish, or Italian, though only trilled once regardless of the place in the word. The r is softer in the Askenazi accent, more like a French r. Both are correct. I find the Sfaradí accent infinitely easier myself, but forms of pronunciation are equally correct.