Well, he's offering the chance for Ewen to retain his good standing with Lochiel and Clan Cameron versus having his name smeared beyond repair to the same. We of course know that Keith and Ewen are both the kind of honour-bound characters who value the true honour held in their hearts above the mere semblance of honour among their fellows -- of course Ewen would turn it down! But if Loudoun's certainty that no Highlander would ever betray his chief comes from external factors -- from the inevitability of the irreparable ruin that would befall said Highlander if it came to be known that he had betrayed his chief... Well, I can see Loudoun thinking that he was offering Ewen a tempting deal.

Vs V pna whzc gb gur guveq abiry naq gur zna jub frpergyl orgenlrq Nepuvr Pnzreba... Gur gbezrag Znvgynaq tbrf guebhtu vagreanyyl, rira nf ur ergnvarq uvf tbbq anzr nzbat Wnpbovgrf, vf rffragvnyyl gur irel qrny gung Ybhqbha vf bssrevat gb Rjra urer: xabj lbhefrys n genvgbe, juvyr ergnvavat lbhe tbbq anzr. Naq bs pbhefr jura Rjra pbzrf gb haqrefgnaq jung Znvgynaq unf qbar -- naq rira gung ur qvq vg sbe cevapvcyrq ernfbaf, juvpu fubhyq unir orra va uvf snibhe! -- Rjra pna oneryl pbzceruraq ubj Znvgynaq pbhyq unir oebhtug uvzfrys gb qb vg...