Can explorers choose not to move?
Yes, you can choose not to move. The rules on movement state:

Moving
On your explorer’s turn, you can move up to number of spaces equal to your character’s
current Speed.

&quot;Up to&quot; includes 0 spaces.
Note that if you stay in the elevator for your entire turn, then the elevator will move again. From the FAQ:

Heroes must roll for their destination floor each time they enter the elevator, or at the end of each entire movement phase that they spend in the elevator without moving.