Not OP, but I'm going to guess confusion between "intake" and the hole in the valve cover where oil goes. I say this because I imagine the result of pouring it into the intake is a non-starting car, not a fire. Cars don't run on 10W-40.
Sure they do. Not very well, and you mix it with gas, but they will run. 2 cycle engines sometimes run 16:1 ratios of gas to oil (an engine old enough to run 16:1 was speced before modern two stroke oils and so they meant regular engine oil - though oils then were very different from modern engine oils). Up until the 1980s a car with more than 70,000 miles on it could be assumed to burn a quart every few hundred miles.
I've never tried it, but I think my 1930 all-fuel tractor could run on 10w-40. I've run it on "it used to be gasoline 4 years ago", ethanol, and diesel.
Well the comment about it "burning a lot of oil" could also be attributed to splashing some oil in the air intake. And it might eventually leak somewhere hot enough to burn.
I agree odds are intake means... oil orifice in this case. But I figure we're already in car abuse land might as well see how deep the rabbit intake goes.
Ironically, if the OP had used straight 30w or 20-50w it would have run out of the car slower causing the car to take longer to catch fire because of less buildup of spilled oil.
To me, when you say intake, I immediately am thinking of the air intake.