This isnt fully tested but ive done it in some raids now.
When a Tectus (Tecti, Tectuses? Whats the plural version of Tectus?) dies, it despawns for a few seconds before it spawns more, this doesnt bring you out of combat, however, as youre not fighting a boss technically, youre no longer sharing Combat Ress with the raid. Ive ressed people like this but im not sure if this also resets the Combat Ress Cooldown or just unlinks you from the boss fight.