Obviously better than my first NMO hole, which while I knew enough not to poke the drill through the headliner I did not think it through enough. The metal sheet metal doughnut that you drill out has to go some place and if it does not stick in the hole saw it will fall via gravity down.
No biggie since I was close enough to reach it through the dome light, I thought. Well, except that the chunk was hot, you know, from the drilling. Oh and the headliner in a Hilux is more plastic-like than cloth-like. So good thing is that it did not get stuck up there after all. But it melted a half moon exit slot for itself.
Second hole went much better since I slid a piece of cardboard in there and wouldn't you know it if the slug stayed in the drill like it was supposed to!