Complex sentence: He modifies a measurement on the blueprints in order to make the trap fail just as in "Designs on Jerry", the trap is set, but the safe (a part of the trap meant to get him) hits Tom instead.
Split into simpler sentences: He modifies a measurement on the blueprints in order to make the trap fail (like he did in "Designs on Jerry"). The trap is set, but the safe (a part of the trap meant to get him) hits Tom instead.