Photo finish

[Oralee]

(n) an [urgent] need to [defecate], usually associated with diarrhea, in which the [bowels] begin to move before the victim has reached the shitter

[Marquetta]

Photo finish in Track Events - General Terms. When two or more letes finish so close together that their times may be identical, photographic evidence is necessary to decide the winner. The victor is the competitor whose torso crosses the finish line first.