How did they film Lane's suicide?

I know from afar it must be a dummy but then when they plunk him down on the sofa he looks so real????? As in dead. Have they just made a fully realistic dummy there and then for that scene or did they switch it out for the real actor when they plop him down on the sofa. I really want to see the behind the scenes footage for that particular scene. It was such a shocking scene that it was fantastically shot and portrayed. Cinema lacks such portrayal nowadays so this was very well done in my opinion.