Here's a situation in which a clerk is robbed, the clerk is compliant and the robber tries to shoot. Fortunately, the gun doesn't fire.
There is a prevailing school of thought that the victim should be compliant until he's pretty sure a robber will kill him, such as taking him into a back room or in a vehicle. In this case, I think the victim has ample reason to believe the robber means to kill him, without any of the normal indicators. At what point should he start to resist, if at all?