Scenario
P1 (host) starts with 2 agents. P2 has 0.
P1 gives his 2 agents to P2. Presses end turn.
P2 presses end turn. Alien plays, ends, P1 then ends his turn.
P2 still being on the starting vehicle, cannot abandon mission.
This is obviously a minor thing to be ignored, since P2 can give the agent to P1 for P1 to press Abandon Mission for him.
Scenario
P1 (host) starts with 2 agents. P2 has 0.
P1 gives his 2 agents to P2. Presses end turn.
P2 presses end turn. Alien plays, ends, P1 then ends his turn.
P2 still being on the starting vehicle, cannot abandon mission.
This is obviously a minor thing to be ignored, since P2 can give the agent to P1 for P1 to press Abandon Mission for him.