Just screened the next episode.
Sandro's frustrations reach a boiling point and things get very nasty.
The challenge -- using bowties -- is the third "unconventional materials" challenge of the season, but at least the ties are fabric.
Sandro is safe, but demands to get feedback from the judges, irritating them and his fellow contestants, particularly Helen and Ken.
DO NOT READ BELOW IF YOU DON'T WANT TO BE SPOILED
Sandro quits, saving Miranda, Sue and Jeremy. Had Helen not had immunity, she would've been in the bottom. Oh there's a nice moment at the end, too.