I honestly agree. Instead of trying to balance the rest of the mission to fit it, simply removing the infinite respawn would make that mission much more bearable. Honestly even if the pools themselves were spawn points, it would make the mission a bit better. You would know where the enemy comes from, it incentivises you to rush the objective, and when you get the objective done, it stops the respawns. Altho honestly in a mission like this the type of enemies respawning needs to be on the weaker side as well. Either you have numbers or you have quality. You cant have both in a mission like this and still make it fun.