But what i was referring is, during the time troops are doing crowd control other Units are mobilised in defensive positions around Beijing's perimeter should other area's unit come in to take over Beijing.
Oh, I get it now. I remember reading that some tank BN had deployed with their turrets aiming outwards of Beijing, & the foreign press took that to mean they're defending against outside units entering their turf. But there was also supposedly a rumor that they only had blank rounds or something.
Hard to say, lah. The "Tiananmen Papers" book also revealed one BDE commander famously refused to obey orders to suppress the students (he was arrested, briefly jailed & disgraced), so I assume the disagreeing factions might have been enpowered only up to that COC level then.
Transferred to local context: Can, say, 1 SIB (or 54 SAB or a PDF BDE) fire on a "mutinous" 7 SIB? That's a clearer scenario, isn't it.
No, still no idea what I'll do. Other than perhaps with 7 SIB, I don't think the SAF has emphasized significant identity building at that command level. Instead, the focus has been more at the Unit or DIV level. As far as those two extremes go, a rebelling unit will be quickly & easily surpassed, while a division is too big for any insurgent army IMO.