Most teachings warn about opening yourself up to the inner levels through meditation without being closely connected to some developed teacher and their past teachers. This is because of the possibility of interference from partially developed beings on the inner levels.
These may be humans who have partially developed themselves while on the Earth or beings previous to humans on the earth (Jinns) or less frequently, beings from a more distant place. They range from reasonably positive to quite negative - just as humans do. The more negative of this range play on people through that persons negative emotions.
Normal humans suffer from their influence and usually only a persons inner guide protects them. If you harbour negative emotions then the guide cannot prevent access through that negativity. If you insist on 'opening yourself up to the inner worlds' through quiet concentration, as some psychics deliberately practice, some foolish teachers teach and some innocent students follow, then the guide is powerless to protect you. It is better to first refine and strengthen yourself internally. Then at a later time the intelligence developed on each of those levels, will gradually, with its own timing, naturally spread beyond yourself into the inner worlds on that same level.
Looking for psychic powers, including the foreseeing of the future, attracts the attention of partially developed beings within the inner worlds. Some of these beings, having existed on the Earth for 10's of thousands of years within the Astral realms and with some connection into the Etheric, they have more experience there than even developed teachers. They can enhance any persons attempt to gain power on these levels and can predict with great accuracy the future course of events on the earth, passing that information on to whoever looks for it. To accept their help (usually unknowingly) is the beginning of a slippery slope under their influence, which begins with an early increase of power and ends with distortion and diminishing energy once well within their grasp. Students are often impressed by such abilities of a 'teacher' - who typically has not undergone long hard training to refine their inner nature with some past teacher who has themselves passed through the same process with their teacher.
With the development of Human#4 (past 3rd initiation) a person is more than equal to this interference, but may still suffer their influence. The main risk with a developed person is the temptation of power. Numerous are the examples of developed people who begin by believing they are the most developed person in the world, then progress to believing they are the world saviour. This is a sure sign of negative influence from the inner levels and will certainly block all inner progress in a Human#4 - worse.
After the 4th initiation (Human#5) a person's field of activity moves from the deepemotional (astral) to the deepmental (celestial), while there being is centred on the 4th energy level. Then that person is beyond the negative influence form these inner levels.