10:54 AM PT -- Cops have a very different version of what went down than what Bruce presented to the crowd. According to the Tacoma PD ... the fan -- a 26-year-old male -- was intoxicated and causing problems with other fans, and when he was asked to leave he refused.
He then allegedly punched a security guard, who called for police assistance. We're told the guy was removed and cited for the alleged assault ... and he declined medical aid.
Bruce Dickinson was so pissed off after a fan got the crap kicked out of him at an Iron Maiden show, he stopped the concert to rip into the venue and its security force ... and the video is wild!
The Iron Maiden frontman passionately addressed the crowd over the bloody incident Thursday night at the Tacoma Dome ... saying, "I hope that kid is getting hospital treatment now because he's bleeding from head wounds. I hope that kid takes this building to the f***ing cleaners!!!"
Bruce says the band has been playing to hundreds of thousands of people on tour, and they've never seen anything like the beatdown this guy received. He wondered out loud to the crowd if this kinda thing happens frequently at the venue. Either way, Bruce says it's "f***ing madness!!"