You Fireball. 30 damage or more kills the Orcs regardless of saves. Then Bladesong. Then advance. Then threaten the two badly wounded Orog survivors with your AC 19 and your Sentinel feat and shield spell (or simply block their escape into room 2)
If they attack you, shield it. Orog 1 runs away, you stop him with sentinel. If Orog 2 runs away and makes it into the next room alerting encounter 2?
Presuming he cant be reached by either of your archers, your party advance to you, with the archers taking the ready (attack) action or finishing off the wounded Orog, and the cleric casting bless on the three of you.
You're basically ready for encounter 2 now regardless of him getting away with ready actions, you in bladesong and the party blessed.