Amp ohm stability in house and car?

I have a spare kicker kx amp I use to free air subs inside to break them in before installing and I always wondered what would happen running at 1 ohm. It is way past warranty period and I didn't mind risking damage so I went for it. I ran it for 9 hours straight inside on 2 subs at 1 ohm at the amp it read 1.4 ohms I put it through a series of sweeps also ran constant from 28-36hz tried some you tube bass heavy tracks no matter what I did it never shut off and is still on and ice cold as we speak. Question is its not even warm and that baffles me so how different is that from being in the car at 1 ohm? Does this mean it might be 1 ohm stable in the car also? Is is less taxing on the amp free airing subs or more as apposed to them being inside a enclosure?