Prediction odds

A running corridor already carries a hold probability P, the same number that priced the position on it. Sideline turns that into a two-sided market, each side the inverse of its own outcome, less the published spread:

Hold   = (1 - d) / P
Breach = (1 - d) / (1 - P)

Both are capped by the ceiling, and a side priced under the minimum is withheld rather than offered.

The odds move as it plays

Entry odds on a running corridor price the time it has already survived and steepen with the distance to the nearest rail. A corridor close to finishing pays the hold side less. A corridor leaning into a rail pays the hold side more. Whatever you take is final when your entry locks, and anyone can recompute it from the signed inputs.

Two inputs change between the author's ticket and yours: the time remaining, which is shorter, and how far the price sits from the corridor centre, which is wherever the market has taken it. Both feed the same double-barrier model.