Maybe there are multiple people at the gala to watch over her because there could potentially be multiple threats to Renee? No one knows how Q will attempt his assassination or even if he has recruited accomplices.
Or maybe everyone has got Q wrong? Maybe he is actually trying to cure Renee’s depression caused by her fear of the space flight (she might be having premonitions)? Perhaps the space flight ended in disaster in the Confederation timeline with the death of Renee and Q is trying to save her from this ultimate doom?