While not having read the books... despite buying it before the film actually hit theaters... I did perceive the progression of minor 'irritation' to 'awoken at 3:01, and battle to already in formation groups'... as 'making things difficult if not impossible' and trying to get Ender to 'wash out'.
He wasn't trying to get Ender to "wash out," though. What he was trying to do was actually mentioned, though so briefly, and so en passant, that it's no surprise you didn't connect the dots. He was trying to isolate Ender, make him feel utterly alone and totally self-reliant, prove to him that the universe was going to cheat him and hard, and hone his instinct to win at all costs. He didn't want Ender to wash out. He wanted Ender to reach his potential.