Why would it be suicide? - He didn't plant the nuclear bomb on his vessel and activate it, he is reacting to the situation and trying to stop it from going off - there is no way that can be interpreted as suicide unless he made / planted the bomb, and set it off when he could have easily deactivated it (knowning it would explode and kill him. An innocent victim unintentionally being caught up in a blast and killed can't be described a suicide)
You are trying to claim something similar to being in a house that is bombed by an aircraft and you get killed as suicide - if you knew it was going to be bombed and refused to leave to get to safety and you could easily have survived but chose not to, then it's suicide. If you were unaware or couldn't do anything to prevent your death then it's not suicide (so if he was trying to wave off the attck or show that they surrender in this case but they are still bombed and killed, it's not his fault that he was killed as he didn't act in a way to deliberately bring about his own death when there was an easy way to avoid it)
