In the part that can be accessed (2nd link) they mention it's a within-subject setup so yeah "with all 5 subjects simultaneously" is correct. within-subject bas

In the part that can be accessed (2nd link) they mention it's a within-subject setup so yeah "with all 5 subjects simultaneously" is correct. within-subject basically means each subject gets all the treatments as opposed to between-subject which is the typical A/B-test setup.