I've also used the "think of yourself as multiple agents" trick at least since my first read of HPMOR, and noticed some parallels. In stressful situations it takes the form of rational!Calien telling me what to do, and I identify with her and know she's probably right so I go along with it. Although if I'm under too much pressure I end up paralysed as Brienne describes, and there may be hidden negative consequences as usual.