Exactly this.
I'm pretty sure all the coded concrete vs steel slats we've been hearing is them trying to negotiate terms of surrender. Concrete kilns or concrete boots = execution vs steel slats = prison.
Notice trumps continued emphases on Strong barriers. He's saying if you turn yourselves in we won't execute you. You will spend life in prison but you will live even though you may not deserve it. The Strong barrier is likely a signal that they'll be safe from any mob that may want to finish them off. The executive order is the go signal on the roundup. It keeps getting pushed back because some are still holding out and they are giving them every opportunity to do the right thing. Some obviously still dangerous likely on a smaller scale.
They have 4 options: Suicide, going down fighting, Execution and Life in prison. Trying to run is not a viable option, trying to silence trump is not a viable option.
If half the country wasn't still under a sleeping spell this could have happened a year ago. That said, never lose hope in the ultimate goal of rooting out evil. Collective conscience is absolutely real. There is more power in positive thought that you could ever imagine.