Nope, he's pretty suicidal. We both went down but he refused to return. That screams suicide to me. And you cannot say that Lee wouldn't have wanted to mercy kill Ben. After all some of us did shoot Duck. My Lee also killed Andy and Danny, so yeah this argument is invalid.
There was no reason for him to die at all, that's why it was dumb, hypocrite, suicidal move.
As thestalkinghead, he could've saved his heroics for Clem.