Looks like you just need to slip the unit back in, being sure to get all tabs in their proper slots. It likely wasn't fully seated on reassembly and popped out when the door was shut with authority.
There should be at least two tabs on the leading edge of that assembly, can't remember right now what is on the trailing edge.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.