#4 spark plug popped out

Real hard, Likely needs a helicoil thread repair.

The "Timesert" is the only Ford approved repair for an ejected sparkplug on this engine. I would NOT drive it until repaired.

Right, Timesert is best and has alot more cutting, in this case is better, I say helicoil when thinking thread repair (but meaning it can be repaired).

It still may me be best to remove the head to do this, but just start with the piston down all the way and then afterwards vacuum it out good (may need to get some attachments or make/improvise your own for shop vac.