From what I can tell, the code for applying 5 ticks of muteness if you try to speak while suffocating is run AFTER the code for checking for muteness and the code for actually saying the message. Thus, if I'm correct, while suffocating, you can say one thing before being muted for 5 ticks (after which you can presumably say something again).
... Despite the best efforts of https://github.com/TheSwain/Fulpstation/pull/285.
From what I can tell, the code for applying 5 ticks of muteness if you try to speak while suffocating is run AFTER the code for checking for muteness and the code for actually saying the message. Thus, if I'm correct, while suffocating, you can say one thing before being muted for 5 ticks (after which you can presumably say something again).