It is most likely still in Spreadsheet View if it was just removed from Timeline View.
If you remember the name of the item, then you can search for it by clicking the search icon on the left toolbar (the magnifying glass icon) and searching for the name. Clicking on the result will open the event in the inspector, and if you have Spreadsheet View open, if you double click on the result it will scroll to the event in this view.
If it isn’t in Spreadsheet View, then try searching for it in Outline View instead.