Flat or Very Low Tire?

So, My front left tire low pressure came on a week or so ago, followed shortly by ALL three of the remaining. I've been meaning to get to a pump for them but haven't.



I was out and hit a bit of rough pavement, and shortly after the front left tire has been riding very rough (thumping like a flat otherwise might). My first inclination is that it probably blew - given the low pressure and combined hit with some rough pavement.



However, a few things have me second-guessing it...



1. It was the first tire to show low, so perhaps it's just now EXTRA low but not damaged?



2. The tire pressure indicators are showing "yellow" - do these turn any other shade if they get super low? Red?



This just transpired here tonight, so I figured I'd wait until the morning when it's light to sort it all out. I have a small air compressor I can use to fill the tires and see if that does the trick.



However, for those of you who have blown a run-flat on your 5, does this sound familiar? I'm PRETTY sure it's blown... just seems too rough to just be simply low pressure. I was going to also take a peak at the manual to see if the iDrive is supposed to show something other than "yellow" for the tire if it's "dead" - like red or something.



Thanks for the feedback!