Arsenal are in range of Newcastle and City at the moment so I wouldn't say they are safe and they have lost 3 of their last 5 games and drawn 2 in all competitions and their next game is against Newcastle and if they lose they can get past them. But I don't think it matters other than the money for a place in the Premier League, there is a winner and that's all that matters, everything else is just statistics.
Arsenal only needs to beat Newcastle to settle their runner up status in the Premier League, tough to settle the scores in as much it will be hard on both teams i believe in Arteta and his team will be controlling and winning the game, it is aswell to be played at the Emirates, the home of Arsenal if 3 points should be given to any side Newcastle are not going back with the 3 points. Arsenal last game will be against Southampton, another 3 points for Arsenal, irrespective of what they did to Man City now that Arsenal are in better form.
Arsenal and Newcastle's game would be an interesting one to watch but I don't think that arsenal can win Newcastle in their current state.. Newcastle are coming for the second position and they are eager to get it... I don't know if arsenal are still weighed down by the fact that they got kicked out of the champions league... Liverpool has nothing to fight for so I expected them to win Liverpool in their last game like Chelsea did but unfortunately the game ended as a draw.