🚀 go-pugleaf

I have Duke3d 1.1, episode 1.  I have not messed with this in a LONNNG
time.  Anyhow, I am now on level 4, where you get washed down this
sewer.... You're basically in a room full of water, swimming around, and
I cannot seem to get anywhere.  There is a button you can press, which
causes a peice of the wall to open for an instant (very useful for
squishing monsters.), but you can't keep it open long enough to run
behind the wall.  Can anyone help me out here?  I know about the one
"secret button", that you can't see, but which does the same thing as
the one up high on the wall, but still, not enough time to run behind
the wall, even with steroids.  Help would be appreciated... Thanks.
:-)  -- Jim