Why was Emmet there? Why did he shoot Emmet in cold blood? Couldn't they just both attack Goodman and forego all the secrecy? He's big, but probably not a match for both.
Did Howard really think he could keep fooling them for one, two years? Usually, kidnappers have the victims behind bars and they are not released. Ever. If he was a full blown psychopath, that would be the way to go. Howard comes across as half crazy... and half a lonely man in need of company given the fact that he cared for his 'victims.' But if he was serious about bad shit happening outside, and the final 10 minutes confirm that he was, then why antagonize the Winstead character further by shooting Emmet in the face even though he confessed they were up to something?