Indeed.
There are lots of people in the rehearsals - not just Gio but other dancers, choreographers, technical crew, production staff, plus the possibility of unauthorised people getting in. It takes very little imagination to come up with all sorts of things one of them could have done, or should have done and didn't.
Maybe she was physically or sexually assaulted. Many people have jumped to that because it's a common experience for women.
Or maybe there was an organised hate campaign or vote rigging campaign and someone in the rehearsal room let slip they'd been involved.
Or maybe there was a warning about a stalker, insufficient security measures were put in place and the stalker got in.
Or maybe the production company wanted footage of them dancing on one of those window cleaner hoists, she slipped and almost fell 30 storeys.
Maybe a lighting rig exploded.
Endless possibilities.
Or maybe it was 'only' workplace bullying. And, if so, that's unacceptable behaviour too.