There are three organ works by Mushel: The Uzbekistan Suite, the Samarkand Suite and the Six Pieces. There are also a couple of pieces for organ and other instruments. The Toccata is the middle movement of the Uzbekistan Suite, which is in the order of Aria, Toccata and Fugue. Personally I don't think when played in the context of the entire Suite, the Toccata requires any augmentation as its slightly sudden ending forms a launchpad for a musical response, which is the fugue. The same device is used of course in many Preludes (Toccatas) and Fugues by other composers. My own choice is to play it from the original Russian edition which is very significantly different from the OUP version. Noel Rawsthorne says he never actually met Mushel or was presented with a manuscript by the composer, but its a very nice story that has become folklore. Some have likened it to a Cossack dance. Personally I'm not so sure as audiences unfamiliar with the work and not given programme notes prompting them with an interpretation of what they are hearing have said that they hear a Stalinist five year plan and the happy workers turning the wheels of Soviet production! One might guess therefore that the Toccata was one of the pieces actually approved of by the authorities and hence allowed to be published in Russia and Germany. The other organ works are so different in style by contrast: far more lyrical with an almost whimsical quality.
I hope this is of help.