The first person does nothing.
She simply sits on the branch while the others saw the wood around her.
At first glance, she seems cautious. Yet, she is sitting on the side that risks falling if person number 2’s cup runs out.
In other words, she does not cause the danger, but she is totally dependent on the actions of others.
Person #2: The attacker
Person #2 saws the branch between themselves and person #1.
His gesture is aggressive, but from a strategic point of view, it could work: if the branch breaks, person #1 will fall while #2 will remain on the stable side.
It’s not very nice, but it’s not necessarily stupid.
Person #3: Self-Destruction
Person #3 cuts the branch on the side where they are sitting.
In this case, the result seems obvious: once the cut is finished, it will fall with the part it is sawing.
There isn’t really any apparent strategy here.
Person #4: The Paradox
