This is a quick video showing you how to get a free perk on Die Rise during an angry smeagol round using only the knife and the catapult. You cannot shoot any guns or toss grenades or you will lose the chance to get the perk.

First off get the parts from the first two rooms then bring them down to the table to build in the room  downstairs.We only had three players so we had to go up and get the fourth part before we attempted this. It is easy to and faster to do it with four players but it is not to bad with only three players. This can be achieved every five or seven rounds and the perk you receive is random I got mule kick on this one. You can tell when the perk round is coming by a sound effect that happens right before they start t charge. But you need to keep in mind how many rounds it has been since the last attack could be on the fifth or the seventh from the last one. You should be prepared for it and ready with another catapult and a good spot to post up back to a wall preferably.