This is obtained on Taxing Level 1 - 3rd Time Lucky
This level is available right from the start.
Start the level and wait for the 3rd lemming to fall out the trapdoor, once this lemming enters the level, immediately pause and increase the release rate to 99.
This should immediately release the last 2 lemmings behind the 3rd lemming. Make one of these 3 lemmings into a digger, it doesn't matter which. Just make sure the digger is made such that the basher below will be collected.
Ignore the digger for now, and make the other 4 lemmings into climbers for the upcoming wall. Give the lemming at the front a floater.
The digger should dig through to the bottom section and will proceed to collect a basher and 4 floaters (needed for the next bit).
Once the first climber has climbed and fallen (so it is between the spinning cog wheel things), make it a basher (collected by the digger lemming) through the wall to the right so it goes underneath the cog wheel.
Give Floaters to your other 3 climber lemmings (as they become available), once the basher has bashed through, make it a builder on the very edge of the drop. This is in order to collect the basher.
The climber lemmings can now exit the level. Once the basher has been collected, it should be just in time for the digger lemming to bash through the wall to exit the level himself.
Assuming all this has gone well, you should save all 5 lemmings and get about 1minute 25seconds.
The trophy will pop up on the results screen.