I doubt that Arsenal can win this round, indeed both teams still have the same chance, but in the next match Arsenal will face Munich away, of course this will make Arsenal feel pressured and I'm not sure that even if Arsenal uses all their strength, Munich will also do the same thing, let alone competing at home will make Munich more confident to win.
Bayern are unstable this season and they lost to outsiders both home and away, so with Arsenal the result could be anything in the return game, playing at the home stadium will not give Bayern significant bonuses. Let's say it will be difficult for Arsenal to win (this is 100%) but they can dry out the game (like in the game with City) and then there is a high probability that we will see extra time and a penalty shootout.