Just re-watched that portion, he does stay in the area a bit longer than what I recalled in my first watch. My problem was not with him leaving, but with him seeming to leave too soon. I still think he should've stuck around a bit longer within the protection the columns provided. He was going to be good target to Nachetanya no matter what he did, so to me the important part if maximizing the opportunity of getting in touch with Hans.
If he thought Flemie was going to die he wouldn't have left. With Hans it wasn't really all about rescuing him, but laying eyes on him since it creates another witness in Nachetanya, and that would be enough. Though he seemed to think that Hans was still alive to be good enough for him to move on.
From a logical standpoint, reaching Hans was top priority including his survival. So it's all about timing. Did he stick around long enough to ascertain that chances would be that he wasn't around? On first viewing, I didn't think so. On second viewing, I'll give the benefit of the doubt.