Four days, four nights - that's all the time that Transport Workers Union president Roger Toussiant spent at the Tombs as he was released just now. And why? Good behavior, plus this interesting loophole, via the Daily News:

Inmates automatically get one-third off their sentences for good behavior, bringing his term to seven days.

That would mean a Sunday exit for Toussaint, 49, who entered the Tombs in Manhattan Monday night. But state law also says that inmates with a Sunday release date are to be freed the preceding Friday, the Correction Department said.

Way to work the system, Roger! Now, to figure out how the union will pay those huge fines from the transit strike - oh, and a transit contract. And MTA Chairman Peter Kalikow must be steamed.