«Zayd qāma» can reinforce the judgment that Zayd stood, but it does not automatically deny that anyone else stood. Exclusive restriction needs an additional contextual or formal indication.
Fronting the subject, using a clause as a predicate, and expressing restriction can overlap in real speech, yet strengthening, exclusivity, and topical prominence remain analytically distinct.
The simplest test is logical: nothing in the basic utterance by itself entails that another person could not have stood.