In Twelve Angry Men, what is the last thing the jurors hear that might influence their thinking when deciding the defendant's guilt or innocence...

Before he dismisses the jury to their deliberations, the judge tells them that if they find the defendant guilty, the bench will not entertain a motion for leniency in sentencing; the death penalty is the mandatory sentence that will follow from a guilty verdict. This is an important fact that must influence the way the jurors think about the case. They know that what they decide will either preserve this boy's life or end it via the electric chair. Juror 8 specifically takes this information to heart. He votes "not guilty" from the beginning, not because he believes the boy to be innocent, but because, as he says,  "I don't think it's right to send a boy to the electric chair without at least talking about it first." When Juror 8 is making a connection between the passing of the el train and what the old man testified he heard, Juror 3 says, "Nobody can be that accurate." Juror 8 responds, "I think that testimony that could put a human being in the electric chair should be that accurate." Later, Juror 8 "baits" Juror 3 by telling him he is a sadist for wanting to be the boy's executioner. These quotes show that, especially for Juror 8, the judge's statement regarding the mandatory death penalty constantly influenced the thinking of the jury.