The men asked the woman if she was all right and she screamed back ''no''.
They crossed the road to inquire further and were met by Couch who told them to leave.
He threatened to ''call his boys'' if the students refused to leave.
When they remained on the scene, Couch followed through and told his co-defendants, who were drinking in a house nearby, that he had been jumped.
Despite the students being 100m down the road at this point, the men raced out of the house and ran them down.
The first victim was repeatedly punched to the ground and kicked until he was unconscious.
''You're not so tough now, are you,'' Couch taunted.
One of the victim's friends came to help him and made it clear he did not want to fight.
But Shaw punched him, then as he walked away, hit him again, sending him into a bush.
The defendant, along with two others who were given police diversion, then chased a third student who was also beaten unconscious.
''Not one of these men went to the aid of any of the unconscious men on the ground,'' Judge Turner noted.
''This was just thuggery; this was an attack.''
The victims all suffered abrasions and bruises, and one required dental work.
Couch - who shook his head as the judge read the facts - was also convicted of an assault a month later, when he was drinking in the Octagon.
He offered to fight another man and when he refused, Couch followed him down Princes St and forced the issue, punching and kicking him in the head several times.
Crown prosecutor Richard Smith said the defendant's attitude was ''alarming''.
Couch told Probation before sentencing that it was ''just a fight''.
''It's not a fight, it's an assault,'' Smith said.
He also stressed the fact the men in the September assault had rushed to Couch's assistance, albeit on false information, did not help their cause.
''Vigilante justice is an aggravating feature, not a mitigating feature,'' he said.
Couch was also sentenced to 175 hours' community work and ordered to pay $440 reparation; Cross got 100 hours and $1500 reparation; and Robertson-Rolston got 100 hours and a bill for $275.
All defendants were sentenced to six months' supervision.