Luke Hobbs feeling mighty incensed about Deckard Shaw throughout the penitentiary scenes takes on a whole new meaning after The Reveal regarding Dominic Toretto and Elena Neves' newborn son: back in Furious 7, Hobbs had to protect Elena from an explosive used by Shaw when he infiltrated DSS headquarters - both getting thrown out of the window by the blast, with Hobbs landing on his back onto an SUV, breaking her fall. Hobbs wasn't simply protecting Elena - he was making sure her unborn child was unharmed, too. Hobbs being peeved about Shaw and going on a verbal tirade in Fate about "beating [Shaw's] ass like a Cherokee drum" is justified because Shaw could have killed three people rather than two (assuming, of course, Hobbs caught wind of Elena's pregnancy between Seven and Fate).
Cipher's blackmail against Dominic should be obvious in hindsight. Given that he values family over everything, the only thing that could make him turn on his family is closer family.
