Whether Axs is a loser in 4-handed play, I have no idea.

But after the flop, the only thing you have to fear is someone else with an ace holding a better kicker. The chance that 3 opponents (6 card) are holding the one remaining ace is about 12%. Fairly safe bet, plus you have the flush to save your butt if the other ace is out there. It'd take a big bet from someone I know is very tight to get me off a hand like this.