If one can accept that an ooze can be pushed at all, especially by a power such as Tide of Iron or Bull Rush, one can accept that you can free a friend from the ooze with the same power. Perhaps grabbing your friend and then slamming your shield into the ooze to pull him out.
The rules should come first, in my opinion, and then fluff should come next. As horrible as that may sound, it's not really a big deal most of the time. "Engulf" could mean that your friend is slowly sinking into the gelatinous cube, and once they die they are in the middle, immovable, and probably a skeleton. This allows a push attack to be considered more realistic in this particular situation. Sure, if you flavor it as the ooze being neigh impossible to escape, then it doesn't make sense to be able to escape. But why flavor it that way to begin with in 4E? 4E players have generally decided that save or sucks/die should be gone, limited, or have conditions for redemption: specifically, in this case, forced movement mechanics. Redemption might be the wrong word, but what I mean is more than a single die roll chance to not die/suck. (Not saying any other way is wrong, just that those playing a 4E adventure have already bought into that or are learning that.)
Now, if it's a cloud of darkness or whatever, and it is accepted that it can be forced to move, why would the engulfee be forced to move with it? It's not even substantial, how can it "hold" a character that well really? I think that DM's ruling was one, poor fluff, and two, because of number one, a poor place to make the fluff or mechanics stand.
