I think so, because we don't see mother Reimu prior to this; if she wasn't trapped, then she would be with the family (assuming the Reimu is not the one hunting), and if she was caught manually, then the kid would've carried her into per base already.
EDIT: I just read the flashback, but I think it's chronologically after this image (ie she was home run'ed after marisa notices the capture) because reimu doesn't seem that injured, and the kid doesn't have any reason to pick up a broken "ball", so imo the flashback is more of a 'meanwhile, this is happening to the other protagonist...' image.