Lock the ability to leave before 50 waves. After 40+ runs on legend and not a single player willing to help completeit to 50 waves. Its such a total waste of time getting to complete just one 50 wave, over 1hr in time. Adding insensitive to stay is a waste as players will just continue to load out after 10 waves. Lock the ability to leave will actually make player commit to competing the full 50 wave run.