Mood goes up when flatmate threatens to end my life

I've a flatmate who tells me he's going to end my life in the most gory way he can think of. He hates me, he says. He looks like he could manage said ending of life, too. I am disabled, wheelchair-bound, plain & sometimes suffer from low moods, & when he says these things my mood goes UP?!

Say I've got a pain in my stomach, he says he'll slice me up, open said stomach or hang, draw & quarter me, & worse. The pain always stops. I get pins & needles all down my legs. It's fantastic. It makes me grip my wheelchair & screech but normally I have no problems communicating at all. He says it's an orgasm, but I doubt it.

Any ideas??