I'll do my best not mention any spoilers here.
I already own the CDROM version of the game and I have no trouble playing it in DosBox except for this one sequence. It is extremely difficult or perhaps impossible to get through because of how quickly the guards walk. I didn't have this problem back in the 90s so I think it's an issue with modern CPUs.
Can anyone confirm whether the GOG version resolves this issue?
Thanks!

I can confirm I finished the GOG version of the game no problem. Gabriel's own walking speed changed at random times during the game (probably fixable by altering Dosbox settings) but all world characters worked at their correct speeds, including said guards.

Thanks so much for your reply, Zat. So the GOG version runs in Dosbox? If so then I guess there's no benefit to buying it again since that's how I play my CDROM version.

Yeah, probably not. I did it to support the GOG cause, anyway. I own the GK Mysteries box set.

I also got past this part, albeit with some difficulty. I slowed down the CPU speed in dosbox and it took me a few tries, but I finally got past the guards and completed the game.

Thanks guys!
And a big yay to GOG for carrying this gem of an adventure game!