> How could it be done in a way that the probes are not in the line of fire when doing it?
How about from under the surface? We could use a miner to build a tunnel under a narrow passage such that we know where the treads are going to be. Then, when the trap is sprung, the Probe pops out, plants the obstruction, and ducks back into the tunnel.
From the apparent design of the Destructor, it would appear that it is vulnerable to a close-in attack. There are no other armaments than the rockets and they cannot be fired at the ground near it.
This part of the plan is do-able! Now we have to work out what to do with the beast once we have it, and how to keep it from shooting things we really don't want shot. Let's get to work.