Staying gupat is very essential in Gurmat rahini, bahini and saheni. Sings flying and hitting the walls were common during Bhai Randhir's time. There were stories which I can not elaborate further, but the fat point here is that, this sikhs when doing NAAM simran abiyass, were flying, and after the sessions, they found themselves sitting in different places in the sangat, some on top of another, some without their dastar's as it falls off, loose hair (hair knot opened), some had their heads bleeding as they hit the walls and ceilings in great force, some laughing and some crying.
This sikhs with Bhai Sahib ji were very complex in nature but this is what Sikhi was. They all kept this profile very low between others.
There was a Singh (still in New Zealand) who during Bhai Sahib's time had this Naam Ras nectar (Amrit sweet nectar) flowing in his mouth and he did not knew what was hapenning. So, he asked some singhs about this Ras thing, they told him to keep quite and carry on his naam abiyass. But, getting excited, he left the sangat and when to Patiala, where in an incident, he started boasting this with his fellow mates. The next day, he could not get this nectar Ras flowing.
So, he decided to ask Bhai Sahib Ji, and Bhai Sahib reply was why didn't you listen the singhs when they told you to keep quite about it and carry on doing naam simran.
Bhai sahib told this singh to jump off the next water well he sees, and not to disturb him anymore. Till today, this singh has not got this Ras thing.
So, gupat is very important.