But the younger one is, and the less “calcified” one’s pineal gland is, the more one can actually, physically venture into the past. Ironically, the tumor on Steve’s pineal gland has prevented the organ from aging in the same way, allowing him, even as an adult, to move physically into the past. Brianna has done the same thing but has no way back without another dose of Synchronic.
After buying up the last of the local Synchronic supply and using much of it for his experiments, Steve has just two pills left. He is able to deduce where in the past Brianna went and takes one pill to get there. As long as the person taking the pill is physically holding onto another living thing in the past or present, that living thing, animal or human, can travel with them as well. Steve’s plan is to find Brianna, take the last pill and hold her so that they can both return to the present.
The scheme works at first: Steve finds Brianna, although they appear to have transported to the midst of some kind of Civil War battle zone on the New Orleans waterfront, and gives her the last pill. A local, deranged woman approaches Steve and Brianna with a gun. As Steve moves toward her to protect Brianna, they lose physical contact and Brianna returns to the present, leaving Steve trapped in the past.
We only glimpse Steve one more time, as a “ghost” in the present, but it’s long enough for him to see Dennis and Brianna reunited, and for Dennis to realize the enormity of what his friend has done. With Dr. Kermani having committed suicide after destroying the rest of the remaining drug, there is no way for anyone to journey again to the past and retrieve Steve. And with the latter stuck in a time period and place where it doesn’t look like medical treatments are exactly top-notch, it’s unlikely that he’ll be able to live very long with the tumor still in his head.
But that doesn’t seem very important to Steve when we last see him. While his own life is now forfeit, he has taken action to change the lives of others around him. He has saved Brianna and countless others from the terrifying effects of Synchronic, and he has given Dennis a newfound appreciation for his family that will hopefully bring them back together.
While we ultimately can’t control time—“the fire in which we burn”—and while life is random, dangerous and unkempt no matter where or when we are, it is up to us to take what small actions we can to somehow make existence just a little bit less cruel. Steve has learned that lesson, even at the presumed cost of his own life. How many of us would do the same?