There are several chapters in the game where Lucas can pick up a crucifix to gain an extra life for his action scenes. In order, they are:
Confession – Accept the crucifix from Markus.
Alternate Reality – In the right desk drawer in Lucas' office.
Hide and Seek – Go straight down the path until it dead-ends.
Agatha – In Agatha's bedroom, on a table behind where she's sitting.
The Fugitive – In Tiffany's bathroom, between the sink and the shower.
Fate on Russian Hills – To the right of the starting point, at the end of that path.
Where is Jade? - The last room on the right of the hallway.
Bogart – In the middle train car.
Picking up any of these will unlock this trophy.
Solution taken from PlayStation Trophies:
https://www.playstationtrophies.org/game/indigo-prophecy/tro...