During a 10 x 3 session? Then you're doing it wrong. You're not supposed to go so heavy that your form fails.
All in all, I have no problem "admitting" that 10 x 3 isn't "brutally" hard. Sure, near the last couple of sets I start to question myself a little, but deep down I know I can get those reps in strict form. But "brutal", no. There are other training routines I would recommend if "brutal" is what you want.
It's funny, no matter how much you try to drum into people that failure, soreness or "pump" is (a) not necessary and (b) often (but not always) counterproductive, it seems that they still continue to think they're working out "wrong" unless they need a partner to "tag team" the last four reps with them.
The point of 10 x 3, and similar protocals, is to feed the body with decent volume and stress, while allowing it to recover as quickly as possible, so that you could train the same (or related) exercise again -- productively -- within 36-48 hours. Think "Frequency". Not "Brutality".
Now, I'm not knocking HIT or 1-bodypart-per-week-fry-the-muscle split routines; they have all been effective for certain people at certain times. 10 x 3 workouts simply have a different workout goal, and that goal isn't to pulverize the muscle.