Events isn't a "section," it's an alternative view of the photo library (ditto for faces and places). Events simply groups photos by when the file says they were taken.
What you're describing isn't actually possible, so I'm guessing that what has really happened is that the photos you refer to have the wrong date and time on them (this often happens with scanned or old pre-digital photos, or photos taken with cameras that have the wrong date/time info). If this is the case, the photos are simply in the wrong Event -- probably "set" for years ago so they aren't easily findable.
There's an easy fix for this:
1. Locate one of the photos that you can only find by looking at the Photos view.
2. Select the photo and click on the "Info" button at the bottom right. That will show you what date and time the file says it has for the image. It's almost certainly wrong.
3. With the photo still selected, mouse up to the menu bar and select "Adjust Date and Time" from the Photos menu (first choice). The next command down, "Batch Change," will let you do this for a whole group of selected photos.
4. Once you make the adjustment to the date and time, the picture will "move" into the event that matches the corrected date and time.
If you notice that a bunch of your pictures have a similar "wrong" date on them (like a whole bunch that say 1969 when in fact they were shot in other years), you can use a Smart Album to quickly locate them all and put them all in one view. Create a Smart Album that collects all photos with the "wrong" year, then they will be easy to see in one group and correct using Batch Change or individual adjusting. Of course, as soon as you adjust the year the photo will no longer be in the Smart Album.
