Re: aikido vs jiu-jitsu
I think this may be a poor escape to learn for "fighting with BJJ people."
Standing all the way up in the guard like that is very dangerous. The instant you stand up and buck your hips you are easily swept. (They grab your ankles and pull while pushing with their legs. It works very easily, and transitions them into mount on you.)
To correctly emply this sort of pass against someone with any amount of expirence requires very good center (base) and the ability to counter that sweep by grabbing their gi (or head). Once you have acheived good base you can begin to address the closed guard.
In fact, at one point in the video (about 1:40) one of the students almost accidentially sweeps the other with this technique, pehaps without even knowing of it. The optimal time for the sweep was a few seconds earlier; you can see the standing student take a few steps forward to recover his balance after moving his center too far back.
Sticking your arms in deprives you of the counter to the sweep.
I think the correct way to pass the guard here is to apply judicious "atemi" the groin until their legs open, then pass.