Let me first set the scene

The group I DM for is in a position where they are at the mercy of a group of people who are contemplating what to do with the party.

I have decided on a game of chance to decide their fate (It makes narrative sense), and at a certain point one of the PC's may do so badly that their fate is to be killed (Again it makes narrative sense).

The particular method of death is that they are going to be pushed off a very high ledge.

While I do plan to give the player chance to do something to avoid this fate (Running, bribing, fighting, etc.) the gist is that if the player doesn't do anything they will be pushed to their death.

The player may well trust the 'enemy' because there is a likelihood that other members of the party have had amusing fates, and be curious to find out their own.

Further to the above:

Some of my players read this site, so I was trying to be vague, but the players are already 'captive' in this scene, and due to language barriers the level of communication is minimal. As such I can't forewarn the party, and I think having the enemy communicate clearly for the first time cheapens the scene.

The PC's are literally sat at a table playing cards and losing may mean being thrown off a cliff. They don't know the rules, can't read the cards, can't understand much of what is said around them and are 100% out of their element.

Examples:

1. Player draws the king > character doesn't know what it means > NPC's
   lead character somewhere > something potentially ominous happens such as being surrounded by NPC's > character is given his stuff back and set
   free
2. Player draws the queen > character doesn't know what it means > NPC's lead character to a cliff edge (The ominous happening) > character is pushed over

So:

What techniques are there to ensure that this player knows they face potential death, without just outright telling them?

Basically when they get to the cliff edge I want them to have a good idea that they are going to be pushed off.

Note on answers: I am playing D&D 5e but I am very influenced by ideas from other systems so I am happy to hear about how to successfully pull this off as a GM, regardless of system. I don't stick to RAW either.