Chpt 1.3 - Ghelves Locks
Marik frowns a bit when Razsire imply that Ghelve is hiding something, but keep quiet and focus his attention on the locksmith. He hasn't sense anything that would give him the same suspicion, but he is curious to see where the Dragonborn is going with this.
Marik then see Raszire and Filimena approaching Ghelve with a menacing look. While he was previously quite affable, the change of expression now leave no doubt in Marik mind on the fearsome nature of the Dragonborn. The confidence he lets out in his last sentence, combined with his towering form, make Marik think he could just as easily summon the city watch or rip apart the dwarf with his bare hands should he feels like it. The priest has the look of a hound who smelled blood.
In any case, Marik refrain from intervening at the moment, for two reasons. First, because he don't want to mess with Razsire or Filimena efforts by doing so. He never was very good at trying to look assertive. Also, he is curious to watch Raszire and Filimena in action and see what they can do.