People which leave a team after one wave ESO or anywhere before finishing wave 8 can be considered highly stupid... but it happens pretty often when they feel that they are not the highest damage dealers. To be honest, i dont understand that behavior considering that they get 25% affinity and focus from every other team member. I earned 230.000 focus till the end of wave 8... that would have been 57.000 bonus focus for these guys on top of their own earned focus and on top of the 25% they would have earned from the other team members.
These people would never even get close to such numbers without a good damage dealer in the team considering that they could not even kill fast enough and in such a large area. There is even the risk that they would not even be able to finish wave 8 (the C rotation) because there are at least 2 large maps with low enemy population which in return drains the efficiency if the team can not kill fast enough.
People are stupid... but on the other side... not my problem... i can solo it.