Vaidix: The interpretation "When the end comes, grammar rules do not protect you" is outright illogical. It also goes against the spirit of taittirIya upaniSat which proves that one can achieve the highest reality just by grammar rules alone!
Objection: The taittirIya says no such thing. The Supreme Reality cannot be described by words, and certainly cannot be achieved through a study of the rules of grammar. Why, not even the upaniSats can capture His glory.
Vaidix: The scripture does not say this literally, but the upaniSat implies that the highest reality can be known through grammar rules. The upaniSat says: "... These are the mahA samhitAs. Any one who knows these becomes a possessor of progeny, cattle, brahmavarchas, food and so on". brahmavarchas (luster of Vedic knowledge) does not come without acquiring the knowledge of brahman, otherwise it would be a fake or cosmetic varchas or it would mean that scripture is suggesting another way to acquire brahmavarchas other than by knowing brahman.
You can not say that mahA samhita is a kind of meditation but not a grammar rule, because it is like saying a king is not a citizen. You can not argue that only highest grammar rules like mahA samhita can lead to knowledge of brahman but not lower rules like dukRNkaraNA, because even an ordinary citizen can become a king if everybody in the Royal family gets killed. Any other grammar rule is only a transformation of the grammar rules such as maha samhita, as Veda says: "By knowing gold everything made of gold is known. Gold as such is the reality"; by knowing grammar all grammar rules such as mahA samhita become known.
Ofcourse, the highest reality can not be known by just "studying grammar rules" as such, but by studying them and understanding them as being derived from Vedic devas and then understanding that the devas themselves were established in Existence.
It is true that upaniSats can not describe the highest reality because It can not be known by any "means". Any kind of means is within the cause-effect chain. However upaniSats do point to the highest reality not by describing it but by negating the false causality. This much has been discussed. But what is often not discussed, but clearly mentioned by Adi guru is that one should not outright disregard the objects as one sees them. If we ignore a snake by saying "Oh, it must be a rope", it may really bite us! So one should not deny the objects one sees around lest one should become a pseudo-advaitist. We can not rule out the grammar rules because we are currently being ruled by them. If anyone denies this fact, it is a denial of chhandas and is an offence against indra and all other Vedic deities!
So technically the procedure is to know meditations like mahA samhita which have the ability to remove false causality and lead to the understanding that the grammar rules are made of the Vedic devas such as indra etc, and then the next step is to understand that indra etc are in turn perceived due to false causality attributed to Existence.
A note on mahA samhita, agnihotra etc: These are the meditations that belong to the first few microseconds of himkArA stage of the thought cycle. These are quite tough to practice because by the time we acquire the necessary tools to take up the meditation, our chance to do the meditation is already over! In the first few micro seconds of himkArA stage, the mind is swarmed with a number of thoughts which are in fact demands coming in from various living cells in the body. Also, due to other reasons of illogic, people think that they don’t have much time left to decide about these thoughts, and they end up taking wrong decisions. A good decision can only be taken by a person of self control. Through self control alone one can really decide the priority among all those stimuli. And self control is acquired by treating all the living cells in the body equally. It is viSNu alone who treats all the cells in the body equally, by providing food for all of them. Therefore meditation re: viSNu alone prepares a person for a meditation re: mahA samhita etc. But then, after realizing viSNu no further effort is needed, because that is the conclusion of yajJa.