So no matter, someone would be coming for Donny (spoilers)
I assume part of his plan involves Butler and others going after Merriman and the others. One of the two would die, but that just means one of the two lives
Butler survives, and then he goes after Donny (which is what we’re getting in Part 2)
Merriman survives, and then he and his gang go after Donny for double crossing him
Either way, Donnie gets a ton of heat