I'm assuming you have a 2005-2006 5.4L 3V expy, easiest way to reach the number 4 plug for me is to unbolt the PCM and its bracket, you don't have to unplug it just remove the 4 10mm screws holding it to the bracket, move it out of the way and secure it using zip ties or a shoelace, then unbolt the black bracket 3 either 10mm or 12mm screws and remove it. Also unplugging the coils and injectors to cylinder 2, 3 & 4 and moving the wiring harness out of the way and securing it with zip ties helps a lot too.
For cylinder 5-8 I remove the air intake, remove the harness like I did previously and secure it with zip ties, and I would also remove any vacuum hoses that comes between me and cylinder 8.
If the plugs haven't been changed for well over a 100k miles or they're the original ones then theres a 99% chance some will break, if they have been changed before, hopefully the last person used antiseize on the threads and used the updated plugs.
Would be a smart move to have this tool beside you incase any do decide to break.