er i could be wrong about this but back when mew died his helm cracked you can not surive in space without a helm, its not a matter of holding yur breath its more of a matter of it being cold as shit i mean real cold, not to mention im pretty sure that yur organs would like expload out yo body, but this is anime so im not sure.

now if its relly mew only one thing wil be worse if he dies AGAIN im serious bring him back then kill him again and ill throw up