After Benedict had the row with her? I saw him standing next to her but he didn't seem to want to get involved.
Will she be mad at him for not sticking up for her?
It's hard to stick up for her when she instigated the argument.
She could of simply told him she didn't like the way he was talking to other HM's but instead she confronted him in the only way she knows how and that is "SHAT AP! SHAT YA MARTH!"
There is nothing Luke S could possibly do. If he physically attacked Benedict he'd be removed from the programme. If he attempted to have a battle of the wits with Benedict he'd fail and be humiliated.
In this instance saying nothing was the perfect thing for Luke S to do.