You can get there with jump cpu (which jumps to x-1), chance is something like 0.1% so it can take a while
As blackout said you cannot use invisible but those boxes gives also uridium and other ammos.
I have been there twice: first time I tried (and succeeded) to escape enemy with 0 shields and about 40k hps -.- Second time with 2 slow configs, I was going to make gg with kami... So thats my luck^^