Thirukottiyur Nambi agreed to part with the Mantra and its meaning. But before that he got a promise from Ramanauja. As per the promise, Ramanuja should not tell this to anyone as this mantra will take a person who listens to it directly to Vaikuntam and if it is told out to others Ramanuja will go to hell. Ramanuja with great excitement and anxiety got the mantra and started going back to SriRangam. While he was walking thinking of what he heard, all of a sudden he had a feeling and wanted this mantra to be known to one and all in the world so that everyone can reach Vaikundam.
Thirukottiyur Nambi came to know of this and became very angry.
From the above passage its clear that Nambi did wanted him to keep the mantra secret.
It is another matter if later he was convinced or not.
My questions are,
Is this to be considered to be a guru droham ?
If at all ramanuja wanted all to be liberated (which is understood), why he didn't take prior permission for doing so ?
What shastras allow one to go against gurus wish and do it without prior permission?