The story is well know, and I've mentioned it before, here, as I verified it with Reb Yehuda Bakst.
When Harav Bakst was a young man in Shanghai, he was stricken with severe appendicitis, and he hovered between life and death. He dreamed that he was in front of the Beis Din shel Ma’alah, and the Mashgiach, R’ Yeruchem, was on the Beis Din. The members of the Beis Din were arguing about who is more chashuv, Malachim or people. Some said that people are more chashuv, because Malachim can only do one thing, but people can do many things at one time. They then asked Rav Bakst, what does he say, does this mean that people are better than Malachim? He said he did not want to answer. They told him that he had no choice, and he had to answer. So he told them that this did not prove that people are better, because pshat that a Malach can do only one thing is that when he does his shlichus, he does it with his entire being, with all his kochos. But when people do more than one thing at a time, it is because they are not doing the things they are doing 100%, they are not being done perfectly. Even for people, if they need to do something perfectly, they can only do one thing at a time. R’ Yeruchem said that what he said was good, and the Beis Din paskened that he will live. And then he woke up. When the Mirrer oilam wanted to make a shinui hasheim, he refused, saying that Beis Din had already paskened that he will live, and he will live, and there is no reason to make a shinui hasheim.
My son, Reb Shlomo, said this at a Sheva Brachos this week, and he added that the Choson had this quality of giving himself over b'leiv vonefesh to his hasmada in Torah. But he added that Rav Bakst really was saying (or, we can say with Rav Bakst's yesod,) that it is possible to have the maalos of both Ben Adam and Malach. Of course, single minded focus, doing something with all you kochos, is the ultimate. But when a person seeks the one goal of Shleimus, of being a true Eved Hashem, then many other things are just pratim in the great over-arching goal. Everything that he does is evaluated according to its effectiveness in achieving the tachlis of being an Eved Hashem. Such a person has the maalah of a Ben Adam who can do many things, but he also uses the quality of Malachim, to be focused entirely on the one tachlis of life and to shatz opp everything he does with that measure. So the biggest maalah is to have the ability to focus totally on one tachlis, not just one nekudah.
We realized that with this in mind, we can imagine who the other two Dayanim on the Beis Din shel Maalah were (and we were able to connect it to the Parsha.) Rav Bakst said one of them was Reb Yerucham. I think the other two were the Rambam and the Ramban.
It is well known that the Rambam (and the Chinuch) holds that there is only the mitzva of building the Mishkan. All the keilim are not separate mitzvos from the Taryag. When you build the Shulchan, the מצוות צריכות כוונה is the Mitzva of ועשו לי מקדש, the general mitzva of Binyan Hamishkan, because the Shulchan is just a pratt in the mitzva of building the Mishkan. The Ramban says no, every kli is a mitzva bifnei atzmo. True, the fabrication of the Menorah and lighting the Menorah are one mitzvah, but that mitzva, and building the Aron and the Mizvbeiach and the Kiyor, are independent of the general mitzva of Binyan Hamishkan and are counted individually among the Taryag. When you build the Shulchan, you say asher kidshanu to build a Shulchan.
So the Rambam and the Ramban were arguing about this. The Rambam said that the ikkar was the tachlis, and once the person has the tachlis in mind, every pratt is just an element in accomplishing the tachlis. So, too, a person can do innumerable things, but it is possible to do these many things with total dedication and focus on the ultimate tachlis of being an eved Hashem, and it is called one thing. The Ramban said, no. When Hashem gives a tzivui, you do the pratt, you focus on doing what you are told, and it is not for you think about how your particular peula fits into the purpose of the universe. That is the maalah of a Malach; his focus is to do the peulah with which he was entrusted and nothing else matters. Ultimately, it was the Isaiah Berlin dialectic - "The fox knows many things, but the hedgehog knows one big thing"
So they couldn't come to a conclusion, and they said to the third Dayan, Reb Yerucham, which is better. To have the general tachlis focus of a human being, or a Malach's tight and exclusive focus on a particular task. When Reb Yerucham saw Rav Bakst, he said, good, what do you say? Rav Bakst answered that if a person does many things separately, then it is a flaw, compared to Malachim. But if he can have a heavenly perspective, and see that Shleimus HaAdam is the ultimate goal of being an Eved Hashem, then he has the multitasking power of Man combined with the laser focus of a Malach, and that is really what the Ribono shel Olam expects from us.