Kimura’s attitude erects an SEP field around men in women’s spaces.
An SEP is something we can't see, or don't see, or our brain doesn't let us see, because we think that it's somebody else's problem. That’s what SEP means. Somebody Else’s Problem. The brain just edits it out, it's like a blind spot.
(Douglas Adams, The Hitchhiker’s Guide to the Galaxy)
Who else should go unchallenged and be protected by a SEP field? Social transgressors, especially those who transgress sexual boundaries, tend to escalate their behaviours until they are extreme. Extremely harmful.
Was it the staff’s problem to address? He wasn’t a man who had opportunistically snuck into the women’s changing room - the staff had let him in! They had made a visual assessment of his fancy dress and approved his invasion. Maybe they were Jobsworths who thought it was SEP.
Miranda recognised a man causing a problem and addressed it. She did not escalate it, he did.
The police did not have to be called, he called them as part of his socially transgressive behaviour, he escalated the situation.