She didn't mention it but the reason she didn't notice this sooner was because something damaged the tank level meter so that it read lower than it actually was.
She didn't mention it because that's honestly way more information than you need and the comic is already crammed full of dialogue and exposition.
Space walking is one of those things that I find absolutely terrifying, it's like tightrope walking over a pit of spikes, only it might take you DAYS to die if you fall.
Space walking is one of those things that I find absolutely terrifying, it's like tightrope walking