[Mr. McIntyre] had been Grace's adviser, her closest confidant, for half her life. (1.6)
Grace must have thought Mr. McIntyre was loyal and trustworthy to keep him so close for her entire life. He acts pretty shady through the rest of the book, though, so she may have made a bad call. Despite his duplicitous ways, could he possibly be acting in Grace's best interests?
"My dear children, may I suggest something? We need an alliance." (4.79)
Like in Survivor, an alliance is crucial to getting ahead in the game. A good alliance requires loyalty among all its members. An alliance with Uncle Alistair is not a good alliance, because he's only loyal to himself.
[Dan's] arms bled from a hundred cat scratches. (5.102)
This act shows Dan's loyalty to his sister, Amy. She really wanted to save Saladin the cat, but couldn't find him. Dan not only finds the cat, but gets pretty injured in the process. That's some brotherly love right there.
"I am glad we came to an arrangement [...] I did not wish to hurt you." (7.42)
Other teams are making alliances as well, as we see in this exchange between Irina to the Kabras. Of course, Irina has already been described as a former KGB agent, so how loyal can she be? Aren't spies just professional liars?
"Nobody messes with my babysitees" (15.18)
Nellie, a non-family member, is loyal to Amy and Dan despite the fact that they can't even pay her anymore. That unconditional loyalty makes her more family than Amy and Dan's actual family.
Nellie whopped [Alistair] upside the head with her backpack. (15.62)
Nellie is so loyal to Amy and Dan that she'll wallop someone upside the head without even getting their side of the story. We don't know if that's admirable or just plain reckless. But we do know that it makes for a great visual.
"I'll stay behind, as a show of good faith." (15.123)
Despite betraying them already, Uncle Alistair pledges an act of loyalty to Amy and Dan. Of course, for all they know he could be plotting anything behind their back. If you're not sure if you should trust someone, it's most likely because they've proven themselves to be disloyal already. Trust is one of the hardest things to win back—even harder than a million dollar prize.
Alistair charged into the room and knocked Natalie to the ground. (16.66)
This might be seen as an act of loyalty to Amy and Dan. After all, he just clobbered one of their enemies. But this enemy is an eleven-year-old girl. Perhaps he's not loyal as much as he is just a big bully.
"I told you alliances are important. I'm simply making friends where I can." (18.34)
Ugh. Ain't he just the worst? Alistair forms an alliance with Irina, someone who could both out-fight and out-smart him. He only makes alliances with those whom he thinks he cannot beat. Amy and Dan should take this as a compliment.
"Does that include me, too, kiddo? What about our agreement?" (19.74)
Amy and Dan have been told to trust no one, but Nellie makes sure they still trust her. She seems loyal to us, and we hope she sticks it out with Amy and Dan until the very end.