Rybka is just informing Tachikoma what she knows. As you can see, even though us as players know that she botched up her quiet hacking attempt, she does not know it, and would like to keep to the plan. And it seems like she is the one who favours subtlety the most in this group, after all.
But Tachikoma can jump in at any time; the thing is that there will probably be cybercombat really soon (one CT from now)...
Also, I know that about hidden accounts (good thing you posted it, even then, Serious). Rybka is not really worried about that, making it hidden takes too much time, and not all systems keep analyzing this kind of data all the time, most will just checked it's access and change logs once a day.