In the current example text, Player 4 seems not to be warned by the GM nor his own common sense that this will result in a hostile reaction.
That aside, if the player is set upon his character suiciding, it’s best IMO to confirm their knowledge of the risk, then to let them, then ask why after session.
- Sometimes, it’s a character that’s not what the player envisaged. Sometimes, especially in old-school games where the GM enforces “play what you rolled,” it’s a way to be rid of a bad character or a character that isn’t anything like what the player wanted.
- Rarely, it’s a way for a player to drop out of a group and make it look like the GM’s fault.
- In other cases, it’s poor descriptions resulting in not reacting appropriately.
- In a few cases, it’s some secret the player kept about his character that he thought would be cool triggering stupid behavior.
When dumping a bad, undesired, inept, or boring character, the issue is one of expectations. In general, such players should not play in games where the rule is “play what you rolled.” Use of alternate generation methods was instituted in both D&D and T&T for that very reason; Champions, GURPS, and many others went to deterministic CGen methods so players could get what they wanted every time. Less litigious types might allow rolling two or three and picking one to appease such players, or even allow retiring them after some number of sessions or adventures, or even arrange a “good death” for them, and allow them to go out a hero.
The rare cases where it’s dislike of the game – either the system, the setting, or the campaign – it’s a way for a player to quit without looking like their quitting. And often, to save face by making it look like a GM being unfair. In even rarer cases, it’s a player putting the GM into the unfortunate double bind – either look like a jerk for not allowing the suicide, or for killing the PC over a misunderstanding of the situation.
Far more common in my experience is the player not having the same mental image of the situation and/or the odds. Inexperienced players and inexperienced GM’s are often causes for this – and the combination of both can be a comedy of errors. In dealing with this situation, one just needs to confirm that the player understands the risks.
In the case of Secrets, it’s a very common misconception that secrets are best kept in roleplaying games. There are two kinds of secrets a character can have – those the GM should know about, and those that everyone at the table should know about, even tho’ their characters don’t. Any secret that motivates your character should be something the GM is aware of. If it was a case of some motivation or backstory that the GM didn’t read because the player wrote 10 pages of it, get the player to write a one paragraph (of no more than 10 sentences of no more than one typed or two hand-written lines each) listing of the key motivations, including any relevant secrets.
In all these cases, communication failures are usually the root cause. Only in the rare case of the Jerk player trying to make the GM look bad is it not really a communication failure (and in that case, it’s a player error).