Watching him survive with his PTSD and his not-always-legal lifestyle was definitely difficult viewing, and his demise is even more effective knowing that Rupert Friend was personally affected by Quinn’s lack of a traditional best friend, lover or trusted confidante.
That he died saving Carrie’s life is far more important than him saving the President-Elect, or any member of the U.S. government for that matter, because at least she was the closest thing that Peter had to any of those things.
Man, as if it wasn’t hard enough just saying goodbye to Quinn already, especially after everything he’s experienced in Season 6, as his recovery from the sarin gas exposure in Season 5’s finale turned him from an often unflinching professional to someone else entirely.