The thing that is interesting here is that the protesters have basically told the protest leaders who agreed to a truce, "We don't want no stinkin' truce."
Reminds me of an anecdote. There was a coup in a third world country where the most widely-recognized leader of the coup was agitating both within the country and internationally for the overthrow of the government. All the major news outlets featured this individual in their coverage. The coup was successful and within a month, the supposed leader was sentenced to a prison term by the government that emerged from the coup. On his way to prison, a journalist asked, "Weren''t you the leader of the coup?" to which the soon-to-be-imprisoned former leader replied "I guess the coup I was leading isn't the coup that won."
This is going to get messy. I think Putin has to let them go. If he gets crosswise with Ukraine, the oil won't flow and the Russian economy will take a big hit. I don't think he could effectively control Ukraine by force.