So I found out that you can clip trough the wall on the NTSC-J version of the game, sadly you can't skip this on NTSC-U. Didn't test PAL yet tho.
To clarify in case people see this and is unaware: This is not a new skip. We've known about this forever, and it has been done in speedruns for as long as I can remember. It was, however, regarded as a PS3 only skip. This makes the PS2 NTSC-J version slightly less slow compared to the PSN version, and reigns supreme among the PS2 releases.
The reason why it works on NTSC-J is because the NTSC-J version is patched with upgraded paraglider bouncing. This is the same patch that fixes the memory corruption glitch when skipping a certain cutscene in episode 8. I'm not sure if this is also the same patch that fixes the cutscene trigger in episode 5 operation, but I would assume so.
I personally knew the NTSC-J version was a patched version, but I was unaware that paraglide bouncing was changed in this patch. I was under the impression that this was done during the HD remaster port.
tl;dr NTSC-U and PAL for PS2 is of an earlier version where this skip isn't possible. The game was patched before the NTSC-J release, and thus the NTSC-J release is that of a patched version. The patched version was later ported over to PS3 in Sanzaru's HD remaster release. This skip is only possible on patched versions of the game.
So I did exactly like you do it on NTSC-J/PS3 this and it didn't work on the other PS2 versions.