I'm so fucking confused

wait ok so a random omega is going into heat, Rika being an omega himself goes to help said omega, then said omega fucking stabs him with an inhibitor????? Σ( ￣□￣||)and then Rika goes into heat!?!?!?! like what?? Why??? and then!!! random omega dude evilly smiles at Rika and invites in a bunch of alphas who aren't affected by the omegas heat but they are affected by Rika's heat?????? AND THEN! Shiina comes in and rapes and bites Rika. See I can see how the author can build a case to excuse Shiina's wrong doings... BUTT! (づ￣ ³￣)づWHY THE HELL does the author think we should feel bad for the RANDOM OMEGA. Like did I just misunderstand what happened and what the situation was or is this story just fucked in the head?? ALSO! I dont understand how the fated pair dude fits into the situation, like was he there when Rika got raped?? IS THAT WHY the RANDOM OMEGA fucking got Rika raped in the first place? So he could get Rika's fated pair? Cause if so this story is even more fucked than I originally thought it was and if he was Rika's fated pair and he was there, whY dIdn'T hE dO AnYThInG???Σ( ￣□￣||)