Dora's teeth clenched as he received the secret of his defeat.
From the beginning, the true Dora erased regularly parts of his memory using Gluttony on himself.
When he launched an attack, he erased the memory of the location of his targets, when he saw someone coming to him, he erased this memory.
And more than all, using the same process, he manipulated him through the Personas.
They shared the same mind, so they knew what he knew, so when all of them were genuinely surprised by Zury's decision, he lowered his guard.
Dora was communicating with Zury the whole time, but always erasing the memory of their discussion for a perfect surprise effect.
In their shadow, the two conceived the ultimate plan to switch the tables.
Dora had a phenomenal defense and could regenerate, but with corruption, these feats were obstructed.