You know, it is entirely possible (although somewhat unlikely) that we are doing Becky's dad a disservice. After all, we only have Becky's word for what happened when she was withdrawn from Anderson. It is possible that Becky, upset and riding several emotional roller-coasters (including Joyce telling her that there was no chance of anything happening between them), exaggerated events somewhat.
It will be interesting to see everyone's reaction if his first reaction, upon seeing Becky, is to burst into tears, hug her and thank God that she's safe.
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More likely, this whole thing could very easily get hugely complicated. If Becky refuses to go with her father and claims that she is in peril from him, then, irrespective of her status vis the college, the Administrators would be obliged to hand the matter over to the police (possibly even the Feds if state borders have been crossed).
My guess is that Becky's father is one of those men who, no matter how morally self-righteous, has a strong aversion to making a public spectacle of himself, especially in a dispute where he is unlikely to get his way. I think that he’ll decide that he’d prefer Becky within easy reach of someone he knows and trusts (Joyce) than her missing and on the run whilst doing who knows what to support herself. He’ll transfer her to Indiana State but will sternly instruct Joyce that she must have intensive moral sermonising sessions with her at least daily to ‘cure’ her of her ‘deviancy’ and that he’ll hold her personally responsible for the outcome.
This means that we will witness occasional calls to Joyce from Ross asking for status reports, the practical upshot of which will be that Joyce will become a skilled and plausible liar. When graduation comes, it is possible that Joyce may never be able to go back to her home church because Ross will have her cast out for being party to his daughter’s behaviour.