I did that ending.

>! when you continue the timeline, there are these radio transmitters scattered around (one in the bunker at the end, the other, where Clarissa jumped I think and there was another one), that Alex always mentions. You can come up to them and try to tell your future self to never come to the island. Then when the first flashback occurs, Clarissa should mention about how your classmate heard you saying from the radio “don’t go to the island.” I don’t know if it is fully the way to do it, but it happened to me. Then when we spawned at the parking lot for the last time I tried my hardest to not go to the island, so we went to get pizza instead!<