Skip flags.
The death events in Head.tsc have <SK+0010 in 'em.
The Top Floor O door has <SKJ0010:0105.
Skip flags are unset after quitting the game, though.
So can Skipflags be used with <ESC or not? That said, I've been reworking the script for Ending 04:
Most of the script is now in the Head TSC file:
#0044
<KEY<MSG<FMU<CMU0017Would you like to step into the
Anticharger?<YNJ0500<CMU0017<WAI0020<CLR<KEY<MSGDoing so is tantamount to suicide.
Are you sure about this?<YNJ0500<FAO0002<PRI<MS2<SOU0017<SK+0010
Gunnoid-0's life slowly
drained away.<NOD<CLR As it decresendoed
into nothingness,
perhaps he could
have lived and changed the world...<NOD<CLR
<WAI0025<MS3You have obtained
Ending 04:Suicide.<NOD<CLR<CLO<FL+1005<EVE0501
The rest of it is in the Deep Sector area:
#0500
<FMU<CMU0008<END
#0501
<FLJ1005:0502<GIT1033<MS3Alternate Costume #04 (Inverted)
unlocked.<FL+1005<WAI0050<ESC<END
#0502
<WAI0050<ESC<END
#0503
<MNA<CMU0008<CMU0008<FAI0004<SMC<END