They don't provide spacesaver spares on cars fitted with (rft) runflat tyres. The tyre sidewall is much thicker than a convential sidewall,and is capable of supporting the cars weight with no air in them.
A puncture warning system is fitted,which alerts the driver,as a physical inspection may not highlight you have a defective tyre.
The idea is ....
A) put the gunk in via the valve,pump up the tyre with provided compressor, drive at 55mph max and source a runflat replacement asap .
OR
B) keep driving knowing that one tyre has a problem,straight to a dealer or tyre depot that can remove rft tyres (more difficult due to stronger sidewalls), and then continue your journey with a much lighter wallet

BMW use these across the range. Horrible tyres that give a harsh ride. Each tyre costs £220 !!!!
I changed all 4 @ £120 each,bought skinny spare,jack & wheel brace @ £175. The result is a smooth quiet luxury vehicle that cyclist hate! PMSL