The In Purgatio Lumen would require a score of Tech-Priests to keep running even if it wasn’t a sacred vessel to the Adeptus Mechanicus. Despite the excellent work done by Explorator Felicis, even he cannot accompany the Lord-Captain on every mission.

Tech-Priest Taybor distinguished himself during the mission to loot the Promise of Agony when he successfully identified the Dark Eldar technology at work in the mysterious Pharmacia.

Artwork taken from here.