John savage, disgusted by civilization, secludes himself in an abandoned lighthouse and performs situals of self punishment to expell himself from contamination. News about this breaks out and soon, many reporters flood in. He becomes quite popular, eventually drawing in Lenina. He goes on a frenzy, whips her and proceeds to have an orgy. He awakes the next morning to horrifying memories and takes his life. John Savage's final act demonstrates both enlightenment and weakness.
To atone for his sins, John Savage took his life. He lost control of himself that very day. Not only did he break the laws of the World State and its philosophical foundations, he broke his own laws. John, one who believes in god, is desperate to hold onto his own values. He would rather have truth than happiness. Lenina in this case serves as his temptation. His resolve collapses and he succumbs to the thinng he was most against. This gave him the drive to kill and redeem himself as human and instead of some suppressed creature.
John could have possibly taken his life due to fear. Weakness. He was already extremely popular amongst the crowd who has never seen anything like this before. The savage snapped and went crazy. Fear of gaining attention, the desire to run away, may have caused him to take his life. He was trapped in a horrifying world, secluding himself so he could keep his resolve. But, he didn't. Perhaps running away was his only choice. And so, he ran.
John Savage seemed to be one of the only "normal" characters in this novel. He rebelled against civilization's norms and sought out to be his own person. But in the end, he succumbs to their desires which leads him to his own demise.