In multi-player, missions come with respawn module(s).
When a player is dead shot, (alive player) will return false, then almost immediately true if the "revive" respawn template is enabled, then could turn on false if time for assistance is elapsed or if the player activates the respawn menu before; and finally true after player respawns. Just be aware that in that case (respawn + revive enabled), the status of the player is toggling: true false true false true. Then, alive status while player is waiting for being rescued could lead to some error scripts as player is supposed to be alive but in limbo and the dead entity "player" passed to server.

Please BI, could you simplify the player's status during the respawn phase?