That's because you didn't turn it fully off in the first place like you're supposed to, Claret.
How can you taxi out and use the SID chart with it fully off? The certification / permission is to allow this.
From off to swiping on, entering password to swiping to find Goodreader to select aircraft type folder, open FCOM 4 and search the bookmarks for a specific chapter just took me 12 seconds. It would take longer than that to reach around behind the seat undo the strap (your FCOMs are strapped securely aren't they Bloggs?) grab the correct FCOM out redo the strap and resume your scan. Even longer if you are PF and need to hand over...