Welp, dunno how to TL this. Just gonna dump it in the comments section: *BAM! BAM! BAM!* Fuji Kiseki: This is Dorm Head Fuji speaking! Open the door, Grass!! Bamboo Memory: Disciplinary chair 'ere! Fuji Kiseki: Huh!? It won't open with the master key!?
Bamboo Memory: COME AT ME, YA GRASSY BINT!! ONE ON ONE!!
Just "taiman", literally "against MAN" ("man" in English), but is slang with pretty much the same meaning as English "COME GET SOME! ONE ON ONE, BRO!", especially when used by 'delinquent' speaking types like Bamboo Blade.