What irregularities? That he wasn’t immediately Mirandized? At worst, that means that anyhting he said before being Mirandized can’t be admitted against him. But they won’t need any of that - there is plenty of video evidence agaist him (not to mention the whole chase/throwing IEDs at cops/shootout issue).
There are a lot of uninformed kneejerk comments on this point.
Not much of a limiting factor given he wasn't capable of speech when arrested or at last report. Speculation he shot himself through the mouth damaging his throat.