What else should Bell do other than apologize?
I haven't seen a video of it happen; but if she was in a run-through, she had right of way. Most skaters just get up and keep going; they only get one shot at a run through. If she didn't realize she clipped her with her blade, it makes sense she didn't say much then. Crashes, unfortunately, happen. If they weren't in a run through I'd expect more "oh, are you OK" chatter. So Bell might have fault, or she might not.
But either way, if it was unintentional, what else should she do?