(A usable artillery.)

(Apparently, it can only be used by the members of the Elyos Legion that took the fortress.)

(The artillery seems to be working perfectly.)

You use the artillery. You finish the investigation.

(A usable artillery.)

(Apparently, it can only be used by the members of the Elyos Legion that took the fortress.)

You finish the investigation.

(Usable artillery.)

(It seems to be defective and not working.)

You finish the investigation.

(You use the Artillery successfully.)

(You can now use the artillery skills.)

You finish the investigation.