Why does this script teleport players in to mid air...

As opposed to a random block in a specific model?

function spawn(obj)
        local spawnPoints = workspace.gameMap.Spawns:GetChildren()
        local chosenSpawn = spawnPoints[math.random(1, #spawnPoints)]
        table.remove(spawnPoints, spawnPoints[chosenSpawn])
        obj.CFrame = CFrame.new(Vector3.new(chosenSpawn.Position))
end