You could just paste that code into the top of a vanilla GAME.CON, then when you run the game, assign a key to "LOCK SPRITES" which takes the place of the turn around function.
gamevar statsaved 0 2 gamevar htg_t_0_saved 0 2 gamevar htg_t_1_saved 0 2 gamevar htg_t_2_saved 0 2 gamevar htg_t_3_saved 0 2 gamevar htg_t_4_saved 0 2 gamevar htg_t_5_saved 0 2 gamevar paused NO 0 gamevar spritenum 0 0 gamevar TEMPVAR 0 0 define PAUSESTAT 500 definequote 200 LOCKING SPRITES definequote 201 UNLOCKING SPRITES definegamefuncname 36 LOCK_SPRITES onevent EVENT_TURNAROUND set RETURN -1 set spritenum 0 whilevarn spritenum 16384 { ifn sprite[spritenum].statnum 1024 { ife paused NO { ifn sprite[spritenum].picnum APLAYER { setav[spritenum].statsaved sprite[spritenum].statnum setav[spritenum].htg_t_0_saved sprite[spritenum].htg_t 0 setav[spritenum].htg_t_1_saved sprite[spritenum].htg_t 1 setav[spritenum].htg_t_2_saved sprite[spritenum].htg_t 2 setav[spritenum].htg_t_3_saved sprite[spritenum].htg_t 3 setav[spritenum].htg_t_4_saved sprite[spritenum].htg_t 4 setav[spritenum].htg_t_5_saved sprite[spritenum].htg_t 5 changespritestat spritenum PAUSESTAT } } else { ifn sprite[spritenum].picnum APLAYER { getav[spritenum].statsaved TEMPVAR changespritestat spritenum TEMPVAR seta[spritenum].htg_t 0 actorvar[spritenum].htg_t_0_saved seta[spritenum].htg_t 1 actorvar[spritenum].htg_t_1_saved seta[spritenum].htg_t 2 actorvar[spritenum].htg_t_2_saved seta[spritenum].htg_t 3 actorvar[spritenum].htg_t_3_saved seta[spritenum].htg_t 4 actorvar[spritenum].htg_t_4_saved seta[spritenum].htg_t 5 actorvar[spritenum].htg_t_5_saved } } } add spritenum 1 } ife paused YES { set paused NO quote 201 } else { set paused YES quote 200 } endevent
EDIT: Removed unnecessary xvel and zvel code, which was leftover from a failed workaround. I also found a bug: if you lock an enemy while they are dying or dead, then they will come back to life when you unlock. I'll probably post an updated version that fixes this later.
EDIT2: Ok, the zombie enemy bug seems to be fixed now. I added some other vars to store/restore temp data.