I wouldn't head for a script here.. The script in the bespoke example is only needed because we wanted to encapsulate the Sound.
To randomly select from samples I suggest using the MultifileDiskPlayer. Provide it with an array of filenames, then use a little capytalk for the index like: (!Trigger nextRandom abs * 7) rounded. Each time you hit Trigger the index will change to a new positive random value, multiply by the number of samples - 1 you are using.
To randomly select a Sound using the SelectableSound you can use the same code for the selection parameter, just multiply by the number of inputs -1 and add 1 (because the SoundSelector starts indexing at 1 not 0). For example: (!Trigger nextRandom abs * 7) rounded + 1.