Google Sheets: Combine rows and columns to create a database

I have a sheet just like this sample (sheet "Source") that contains multiple events in column A and names of people on cells B1, C1, D1 and so on...

Under the names, there are checkboxes for each row, representing whether that person is going to a particular event or not.

I'm trying to come up with a formula that creates a database where each row represents one event and one person going to that event, just like on the sheet "Goal" so, for example, if John and Steve are both going to Event 1, the database would show:

Event 1 | John

Event 1 | Steve

And so on

The order in which the lines appear on the database is not important, as long as there is a unique line for each person going to a particular event. I'm using 40 events and 5 people just as an example. I don't know yet how many events or people I will have on the final list.

Thanks in advance!