Let's rock! Let's party! Is everybody having a good time? In the world of arena rock, those are common exhortations.

But you know things are a bit different when the lead singer points into the seething sea of human flesh near the front of the stage, says "Turn the lights on over there" -- and then worriedly asks "Is somebody hurt?"

That was one of Raine Maida's big concerns at UWO's Thompson Arena on Monday night when the singer and his three co-horts from the big-league Canadian rock band Our Lady Peace performed for a sell-out crowd of about 5,000 young fans.

This was an exciting show. But the credit for that shouldn't necessarily go to the musicians.

Although the guitar-based quartet delivered its big-selling brand of power rock with polished poise, the band's performance seemed strangely tepid and restrained.

And that may have had something to do with the physical drama which unfolded in the crowd -- a drama which, at times, seemed far more riveting than the show onstage.

Most of the fans seemed largely unmoved by the evening's opening act, BTK, and its rather genteel brand of hip hop. (When one member of the quintet yelled "One more song and we're outta here," the crowd cheered.)

But the action in the mosh pit started heating up about 30 minutes before Our Lady Peace emerged. In fact, the night's first crowd surfer was spit up into the arms of the blue-shirted security staff while a Twilight Zone episode about a ventriloquist (Cliff Robertson) haunted by his wooden puppet was projected onto a giant screen at the back of the stage.

Several dozen body surfers had been hauled out of the throng by the time Our Lady Peace cranked out the first chords to Automatic Flowers, the opening track on the band's second album Clumsy.

And by the second song, the scene resembled a Breughelesque vision of hell, as loose-limbed bodies were lifted along by anonymous hands and then hurled into the moat-like space separating spectators and stage.

Moshing and crowd surfing are nothing new to modern rock. But it was clear that even the band recognized the potential danger here.

"This is quite a volatile situation with so many people on the floor," Maida said after the band's second song. "What you have to do is very simple: Just be friends with each other and take care of each other."

It's unclear whether his well-intentioned plea worked or not. Like an assembly line churning out widgets, the throng never stopped flinging up bodies.

And the music?

Well, from an acoustic perspective, that was predictably disappointing. Thompson Arena is, after all, nothing more than a giant, concrete box. And in that sort of setting, loud-volume rock 'n' roll tends to flatten into a muddy mix of noise -- the effect is akin to putting an iron helmet on your head and then whacking it with a ball-peen hammer.

And though it's difficult to know for certain whether the band consciously scaled down the dramatic aspects of its show for the sake of safety, Our Lady Peace appeared less than ecstatic to be here.

At one point, Maida, guitarist Mike Turner and bassist Duncan Coutts turned their backs on the crowd and clustered defensively around the drum kit of Jeremy Taggart. It must be disconcerting for a band when its music -- even music as intelligently humane as the songs of Our Lady Peace -- fuels a sense of feverish peril among its fans. It's a pity. Maida is an evocative storyteller and his deceptively disjointed lyrics offer clues to some startling narratives. But when you're worried about people getting hurt and you can't hear the music well, it all seems a bit irrelevant. Out back, the paramedic ambulances seemed reasonably busy. Were there any injuries?

"A few," said one attendant. Nearby, a young girl -- her foot wrapped with a bandage -- was lifted from a wheelchair into a waiting car.

Soaring rock. A terrible venue. A clumsy crowd.

At least the T-shirts looked enticing.