Ice melting on the foor? A big ice block.
OK, so he could have been standing on the ice block and waited for it to melt.
Now, I have had experience in defrosting freezer cabints in fridges. I'd turn off the thing, take out anything which was not frozen solid and stuck to the icebox (Adam and Eve, for instance), and wait. Four hours later, I'd have a few drips to clean up. In the end, I'd got to the hardware shop, buy a hammer and chisel, and chisel all the ice, sausage rools, and ancient biblical characters out of that freezer. After throwing copious amounts of hot water into the freezer, I'd be able to chisel a little bit more.
OK, so now there's a person standing on a huge block of ice, with some good noose around his neck, standing and waiting for the ice to melt. So he's going to be waiting there, standing upright, for three or four days for that lot to melt.
So he's got to speed it up a bit.
Obviously, if he takes his shoes and socks off to warm up the ice a bit, he'll catch his death of cold.
So he's got to do something else.
So he turns on the truck to warm up the room. Voila! Viola! The room is filled with carbon monoxide and it's taken a mere 15 hours to his unfortunate demise. And the 15 foot high block of ice has melted by the time the truck runs out of petrol some 43 hours later.