Well in case anyone is wondering what the sound of a flat runflat is, I now know. it makes the whole side of the car vibrate. It's not like the thump thump of a regular tire, it's much more extreme then that. It was loud and really rough, I heard it over my loud music even, well probably felt it.
I just got my first flat, luckily I was leaving the house and figured it out before I'd gone a block. Of course, I call Craig and tell him the car is making an awful sound.
The TPI came on a few days ago, but that happens on and off and it's never meant anything so like an idiot I just push the button, it goes out in a few miles and I forget to check the tire pressure. It never came back on and I drove for several days. After giving this tidbit to Craig he suggests that now would be a good time to check the tire pressure. I had 3 tires at 30 psi and one at 0psi. A HA! He's such a good Best MINI Friend Forever (BMFF)
So I limped Tigger home and put air in the tire. So far it's holding. I'm not going to drive him till the morning, see if it's still got air then.
The lesson I learned is that sometimes the TPI is right, and every time that thing goes on, check the tire pressure. Hopefully I don't need a new tire, because I've got those Pirelli Snow Sports on and no one has them in stock.
Ali