Elevator Task if somebody need
1. First you must collect the Dynamite. During the play Buddie gives you the Security Card which unlocks the room where the Dynamite is. After that go on the 3rd floor and go right. From there go south and inside the room (Picture 1). There you can collect the Dynamite, Serum and chat with Andy through ventilation hole. But be aware to have free Heart Container on Valerie before you pick up the Serum or you'll miss to earn the Heart from Valerie.
2. With having Dynamite go into the woods. Climb on 1st rope then go left. From there follow the screenshots starting from Picture 2.