Knowledge is power. Guard it well. Know where to share some of it to keep the rest of it. 

"Lady Sarra patches me into the magna-vox hailer network. You stand by my side as I make a proclamation pacifying the crowd. I tell you the answer to the riddle, proofs attached.", Secunda winced as she made another step towards the edge of the platform. "Should I say something too beyond pacifying the crowd or should you find my answer unconvincing, well, I bet that bolter is not just for decorative purposes."

Toros has secured her position, not in the least, through Astartes support. Addressing the crowds with a visible support of the First would provide a reminder, decently rhyming with that blood-soaked past.