This may be one of those "you had to be there" things, but I'll try and explain it the best I can because it made me laugh
I apologize in advance for my long-windedness.
Last night I was playing Exoddus and as finishing off the Brewery. In one of the Zulags (I forget which one) when you're up against two fleeches while you try and save four mudokons. At first they're behind a gate and you need to pull a lever to open up the gate blocking the portal (which also opens the gate the fleeches are behind). I saved the first mudokon by quickly chanting before the fleeches kill him and then I trap the fleeches behind the gate with the portal then go off to the screen to the right to find three mudokons (and some electric gates with a switch, which in retrospect I was probably supposed to use to kill the fleeches). Anywho, I have to go back to the portal with the fleeches to save those three mudokons and I set them right next to the gate before I pull the lever and chant to have them quickly escape before they die.
Funny thing was, however, the game glitched and closed the portal after the first two but while the third mudokon was leaping at it. The poor third mudokon fell right through the floor and disappeared (he didn't escape or die, as neither counter on the progress board tallied it, he just up and vanished). I had quick-saved before and tried again only to have the same glitch happen. I fixed it by having the mudokons stand a few paces back.
It gave me a good laugh, though. See if you can replicate it, as its a little boring to read about but much more amusing to watch.