In the beginning, Shadow Soul was indeed very cautious and conservative.
She pondered whether there would be a door at the end of the secret passage or if someone would guard it, and whether there might be traps or an ambush inside.
That's why she specially used "Corpse Preservation" to conceal herself.
To ensure she had enough mana to handle emergencies, she found Miss Janet, who was happily entertaining a client.
As a Blood Magus on the Path of Love, Janet could use her life force in place of mana to cast a lesser version of spells. Janet's Path trait allowed her to actively connect with a target and use her own life force as fuel to bear half the casting cost for another.
Although the Foundry, Shadow Soul, and Janet were not strictly teammates, they were acquainted in reality. They had a basis for cooperation.
The Foundry, being too impetuous, had voluntarily given up on this ritual. Since the ritual was difficult, the two of them had to cooperate closely.