Hand over OR keep the Item 1156 fragment
Mechanic offers 1.5M Roubles for the fragment. The KEEP option preserves Item #1156 specification for the Ticket evidence hand-in to Mr. Kerman.
This is a Savior-critical choice — and the trade-off is real money vs. ending access. Mechanic will pay you 1.5 million Roubles for the fragment, which is a lot for a new player and tempting. But: handing it over voids Item #1156 specification, which is one of the eight Major evidences Mr. Kerman demands in The Ticket. Hand it to Mechanic and the Savior ending becomes literally impossible — you'll find out 30+ hours of play later when Kerman asks for the evidence and you don't have it. Keep the fragment, eat the lost Roubles, and you preserve the Savior route. There are no take-backs once you click — choose Keep.