"It must be over 50 years since I last killed a human for blood."
That’s what Hal says to Mary in 5x03. I’m still trying to work out the implications of that statement.
Hal is a man who is very precise with his words – and never more so than when he’s explaining, or excusing, his own behaviour. So what exactly is he saying here? And what is he leaving unsaid?
As far as we know, Hal hasn’t killed a human for blood since 1955. That much seems to be true, but it’s about the only thing that is. We know that Hal killed a pair of budgerigars at the miniature circus in 1957, and at least partially ate them, so we know that he’s killed animals for blood. In series 4 we also saw Hal knowingly drink human blood, even though he didn’t kill anyone to get it. But we have seen modern-day Hal kill: he murdered Larry shortly after having that conversation with Mary.
I suspect that Hal may have done other bad things that we haven’t heard about yet. After all, Hal doesn’t simply say it’s been 50 years since he last killed a human, he says it’s been 50 years since he killed a human for blood. Hal’s choice of words suggests that he’s killed human(s) for reasons other than feeding.
That isn’t as implausible as it might once have sounded. Series 4 gave the impression that Hal spent those years with Leo and Pearl isolated from the world, never leaving the flat. 5x03 has shown that this isn’t true, that Hal left Southend to visit Mary, at the very least. (That’s a piece of character development that I’m unhappy with, but it can’t be ignored.) I can’t help wondering what else Hal got up to while he was out from under Leo’s watchful gaze.