your script’s fine for single row
but Multi row variable set is a different thing.
Put the logic in a Variable Set Client Script on the MRVS and use g_sc_form for the cells
read the parent Facility from g_form, then add options to the MRVS column with g_sc_form.addOption

for example
g_sc_form.addOption(field, 'B - NEWBORN', 'B - NEWBORN');