Danny is Luke's omega and Matt is Jessica's. The bad guy has figured this out and has managed to subdue them all. They have chains that Luke and Jessica can't break and position the four so only Jessica can reach Danny and only Luke and reach Matt. Jessica and Luke can reach each other. Forcing Danny and Matt into heat, they think Luke and Jessica will try to get to their own omegas at first but eventually won't be able to stop themselves from going for the omega within reach. Which will lead to them fighting each other in front of their omegas.
The last thing the bad guy expected was for the alphas to work together to take care of both omegas.