Diana spots security

As Nim touched up Alia’s makeup, Diana took the opportunity to murmur to Jason, “I saw the armed guards posted at the eastern and southern doors, as well as the entry.”
“But--”
“They’re spaced too evenly against the wall.”
“I’m not a fool,” said Jason.  “There are members of the security team dressed as partygoers as well.”
“Two by the buffet, one by the musicians, and at least three near the western perimeter.”
Jason started, his surprise evident.  “How the hell did you spot them?”
Diana frowned.  It was obvious, wasn’t it?  “I can tell they’re carrying weapons by the way their clothes hang.  And they hold themselves differently than the other guests.”  Jason’s eyes scanned the crowd, and she wondered if even he could spot where his people were.