that's a big size actually. and let's not pretend they're doing due to lack of space. you don't put your HQ under the biggest hospital due to lack of space. you don't stash your rockets under a school due to lack of space. they know exactly what they're doing and civilian casualities is just another weapon in this conflict. for one side at least.
As we speak Israeli warplanes have just targeted a convoy of ambulances carrying patients too critical for Gaza's hospitals to cope with and who were on their way to the Egyptian border for treatment abroad. The convoy's departure time was announced to the IDF and the world but the IDF added them to the death toll regardless.
But we've already established we're talking about underground facilities. They're largely underground in the city as well. I don't see what the need to farm has to do with anything.