I remembered his ability is just barely have enough leeway area to protect 2 adults and 1 kid who huge each others tight from landslide in early chapter(him,arthur's dad and MC)
so I guess his power isn't enough to protect everyone but most likely enough to save himself and the kid. the problem is, last time it happened, it was landslide which didn't completely buried them and there're only allies left to recover them later. this time it's gonna be caved in in worst case and there're also unknown army bombing them from above. I wonder how they gonna resuce them later
and like others comments said, convinced soldier at that moment would took too long so it's probably better to "order" him to act independent in roundabout way.