Tim might be in trouble because he might not have the fan base that a Judy Murray or a Scott Mills has to avoid the dance-off after a poor dance. Natalie is usually so good but I don't think she did him any favours with this one.
If Tim does drop in the dance off, he only stands a chance against Scott or Judy because I think the judges would probably save Jennifer over him unless Tim really pulled it together in the D/O. I'd be surprised if Tim stayed were he in the dance-off because Scott and Judy have more public support and profile despite being worse dancers.
Simon might drop in but I think he'd survive anyone except Steve and I think Steve will be OK although Donny's marking of Scott ahead of him was strange and didn't do him any favours.