لَوْ رَأَيْتَ مَا رَأَيْتُ!
If only you had seen what I saw!
The result of this conditional expression can be left unspoken. Depending on the scene, the listener may complete it with amazement, fear, or delight. Ellipsis invites contextual completion but does not establish one exact missing clause in every setting.
The reconstruction must follow the setting. The rhetorical effect is the force of a suggested yet unexpressed result, not a license to quote an invented completion as though it appeared in the source.