My solution to the immortal overlap presented a certain question regarding the earlier ineptitude of the two immortals who pursued Magus earlier. With the ability to remain unnoticed by others on that layer of reality, they would have been able to hide their presence from Magus, which would have opened up all sorts of possible strategies for them.
Granted, it's heavily implied those two are a bit inept, so one may not have questioned that. This does mean, however, that certain younger immortals aren't capable of hiding themselves from Pandora, but she is fully capable of hiding from them. That probably isn't an important detail.