You might want to reference save_post() and do this:
function schedule_out_of_office( $post_id, $post ) {
So that the $post is available to you as well. Maybe the data you’re looking for is in there.
If this doesn’t help you with your question, please describe the use case — if it’s for creating new events or updating existing events — maybe adding the other code snippet would help provide some context… but I hope the $post object will be sufficient for your needs, as suggested above.
Please let me know how this goes for you.