With riveting performances in films such as "Hell or High Water," "The Messenger" and "3:10 to Yuma," Ben Foster established himself as an intensely serious actor who goes all-in for a role. With this year's "Leave No Trace," Foster takes that same intensity and brilliantly turns it inward, portraying a laconic veteran who suffers from PTSD and survives in the woods of Oregon with his teenage daughter, played by Thomasin McKenzie. Foster talks about working with McKensie to establish the connection they needed, why he took performance enhancing drugs to play Lance Armstrong, and the "emotional erectile disfunction" of over-directing.