It sounds like from what Bryan was asking, he wanted to access the selected items from a multiselect choice field in OnEdit or OnSave of the SharePointIntegration object, which is before the item actually loads, which is why he needed it from the SharePoint list as well and not the Choice DataCard. I needed this as well, as I use the Variable that I store the data from a Gallery field to show/hide other fields, and these show/hides wouldn't work when going to edit or View the Form since they are based on the table Variable that stores the Gallery. Here's what worked for me:

OnView/OnEdit: In these modes, the SharePointIntegration.Selected object represents the current item. You can access the multi-select column's value from this object. For example, if your multi-select column is named "Categories", the DefaultSelectedItems property would be set to SharePointIntegration.Selected.Categories.