EMS ameterasyu or rinnegan ameterasu? And yes he can tank it but he'll burn to ash regardless also rinnegan genjutsu would neg him anyway, ameterasu does burn slow but saauke can just use enton and we all know what happens when he uses that. But as for ameterasu itself it depends on how much concentration sasuke is putting into his eye. If it's a little then he still gets burned slowly but if it's much concentration, fast incineration is fast. Remember saauke actually concentrated when it came to bee so that is a factor unlike when he was against A