What that meant is that the only people who would bump into each other are those who are actually on that floor and who are bumping into each other anyway.
Αυτό σήμαινε ότι οι μόνοι άνθρωποι που θα συναντιόντουσαν είναι αυτοί που είναι σ' αυτόν τον όροφο και που συναντιούνται έτσι κι αλλιώς.