it might be cheaper to just transfer her but ethically you wldn't want someone else to go through that *experience*.
besides, how do you know for sure that her new employer is willing to take her on?
you can't be too sure ..
yes, send her back. buy her that one way ticket and get someone (if you feel you can't handle it) to escort her through the gates.
go to MOM at havelock road, show them the ticket (out of s'pore within 7 days) and they will cancel her EP accordingly.
in the meantime, hang onto her passport tightly and watch your possessions.
it's none of your business anymore (hurray!) once she walks through Changi's immigration glass doors if she decides not to board that plane.