Adrenaline
Sam could feel it racing through his bloodstream, hot, powerful, nearly overwhelming adrenaline flooding through him as he sprinted towards the building through rubble and people to deliver the Allspark.
Never before had he felt so alive, it was incredible, this feeling.
He could understand now, why people pulled dangerous stunts and tempted death, it for this feeling, this total rush that one could easily become completely addicted to.