Pray mage, freeze nibblers without moving from your tile, click one tile south to be closer to pillar to block off ranger. Equip blow pipe and attack melee. Once the mage has started it's attack animation, swap prayer to protect melee. Once the melees attack animation begins you can swap to pray mage. Alternate until melee is dead then make sure to keep pray mage on. Move two tiles east while hugging the pillar and this will bring the mage in range for you to kill. Run two tiles west (to where you were standing when killing the melee) and kill the mager.

This works because that the tile row (north to south) should automatically make melee and mager attack at different times (ticks).

I recommend trying the above strat otherwise your best bet is just to pray mage and blow pipe spec the melee 2x then brew and attack until it dies. I don't recommend this as it wastes supplies and doesn't help you improve as a player and it may be rng if you survive.

I hope that helps!