When the operations of the movement are predicated on the decisions of a small group of Very Political Individuals.

Take, for example, the two Russian Revolutions in 1917.

The first, the February Revolution, started spontaneously, and then was taken up by a wide variety of opposition groups to the Tsarist autocracy, resulting in a provisional government which, while flawed, did legitimately set up democratic elections and pluralism during its short tenure. It had no choice but to do so, precisely because it ('it' here meaning the incredibly broad coalition of groups participating in the provisional government) had no pre-existing central decision-making structure that could make decisions unilaterally and impose them on the rest. When a decision was made, it had to be at least acceptable to a majority of the supporters of the government's factions, many of whom had no set 'party line' to follow. That is to say, pleasing the faction's leaders did not necessarily equate to docility from the faction's supporters.

People are generally unlikely to embrace totalitarianism when 'their side' is not in power; thus, a coalition-oriented balance of power like this is unlikely to result in a totalitarian government, both because the factions themselves are wary of it (not holding ultimate power), and even if the faction hierarchies were in favor, the low level of 'unity' in the government meant that significant unrest from the population was likely to result in factions changing positions, either in the hopes of opportunistically using the unrest to gain support in the coalition-based government, or in simple survival instinct, hoping to preserve at least some of their popularity and support the oncoming fall of the coalition which made the unrest-evoking decision.

The second, the October/November Revolution, was a planned putsch by the Bolshevik Party, ordered from the top-down by a group of 'professional revolutionaries' who answered to no one but each other. When they took power, they immediately began purging their rivals and consolidating power further, establishing government along the same lines of the decision-making process of the movement itself - that is to say, hierarchical and despotic, rather than based on negotiation, compromise, and a delicate balance of power. The Bolsheviks placed a high priority on adherence to the 'party line', wherein dissent was effectively treason of a reactionary sort. Thus, decisions only had to be acceptable to a majority of the decision-makers of the Bolshevik Party - which effectively amounted to a small core of a few dozen men.

When they took over the government unilaterally, by force, without need for coalition work with other factions in government, the Bolsheviks replicated the decision-making process of the Bolshevik Party in the then-new Soviet Union - expelling dissenters and condemning opposition as 'reactionary' and traitors to the cause.

You can find many 'mixed' examples in history, wherein vanguardist movements attempt to seize control over coalition governments during a revolution - sometimes successfully, sometimes partly successfully, sometimes unsuccessfully.

A vanguardist movement is one which operates as the center of a revolution.

Common example the bolsheviks who were the revolution essentially. That is to say that if the government would somehow remove this particular group of people there would be no one to revolutionize. Also such a revolution usually turns into totalitarianism because the movement spooked by the "before" that it is willing to use their enemies tactics to preserve itself.

A cooperative revolution on the other hand is comprised of multiple groups who hate that one specific thing. For example, although not a revolution but enough to explain, the USR and USA working together on the german dream, or the dismantling there of. Both have very different ideologies and under normal circumstances would be at each others throats, the existence of a common enemy allowed them to set aside their hate for some time.