I think you are looking at the word force too narrowly, just as you were looking at the word cause too narrowly before.
Saying a person knows refusing to hand over money at gunpoint could result in death, as you said above, is force; it’s the force of logic reasoned through the intellect. The relevant definition of the word force is “to compel by physical, moral, or intellectual means” (Merriam/Webster). Confrontation at gunpoint is at least intellectual force, in that the person affected is intellectually aware of possible death or injury for refusing to comply when confronted at gunpoint. And of course, as I said, force is part of the definition of cause.
But I hope this can cleared up by looking at how the word force is defined legally in the USA. Here it is discussed.
"Force means power, violence, or pressure directed against a person or thing. Force is a compulsion by physical means or by legal requirement. For example, if A used a gun to force B to use that person’s ATM card or under the malpractice policy clause, the insurance company was forced to defend the doctor.
Force is synonym to unlawful violence and it can be actual or implied. The entry into the ground of another without his consent and the case of false imprisonment are examples for implied force."
Note this in the above description: “A used a gun to force B to use that person’s ATM card” and “Force is synonym to unlawful violence and it can be actual or implied.” The first shows clearly that using a gun to gain an advantage over another is force. The second shows that force can be actual OR implied.