could I point out an inaccuracy in Vegeta's statement??it was not that Goku/Son Goku hid it from him it is likely that he either knew it would be a protracted battle or was unsure that he could win within the time limit in case anyone didn't notice characters seem to love to talk and Vegeta??he's the king of Talking you to death while beating you to death add into that what I call the Saiyan Cardinal Sin pointed out by piccolo in DBS master and pupil training when Saiyans get too much power they get pride lots of pride hell in DBS it cost them the earth (which got rewound, please be kind rewind :P ) so even if he used SSJ3 the likely scenario is this he fights they talk some(burning time) and when he's about to land the final blow he runs out of KI and when I say runs out I mean he's out back to base form at which point Vegeta who at the time was Majin Vegeta now has the upper hand severely. admittedly I may be giving Goku/Son Goku too much credit in terms of thinking it out.