Problem: a player with 10s before respawn left can enter the queue in a rally, blocking it until he spawns. Even though if a different player spawns, the 5s cooldown would have already run out by the time the queued player is able to spawn. If there is a double/ triple rally, all are blocked.
Instead of the current system, for every dead player, look if spawning on a given rally postpones the arrival of any queued player. If not, show them that the rally is free and let them spawn before the queued player. If not, show them that the rally is queued.
Example: player A is queued on a rally with 9s left. Player B has 2s before he can respawn. For 2 seconds, let player B queue in the rally before player A. For another 2 seconds, let the player spawn immediately. For another 5 seconds, show player A that the rally is queued.