I wonder why this guy was trying to look at ROM inputs as binary bus trying to figure a truth table. AFAIK, they are selection lines from decoder, hence only on

I wonder why this guy was trying to look at ROM inputs as binary bus trying to figure a truth table. AFAIK, they are selection lines from decoder, hence only one of the lines can be active at a time, i.e. depicted ROM is only 5 words of 10 bits each.