Hmm, you didn't mention how you saved the blocker or how you trapped the crowd. Here's how I did it:
Lem1 digs where he lands, Lem2 turns and climbs,
floats just before he lands. As soon as Lem2 is out,
RR=99. Make the digger bash out to the floor of the
pool, and the crowd won't die.
Lem2: Build on the very edge and bash to reach the
ceiling. Mine down and dig/build to turn him at the
right moment and mine into the pit to create a path
for the others. Bash if necessary.
If he built on the edge originally, he will climb
the wall and fall back down. That's what I did, but
it's probably possible for him to climb back up and go
around again in time.