Option 1 - Let us cancel the respawn time
Canceling a respawn is a much needed tool so teammates won't have to waste their precious time trying to revive you and then fail just because your respawn timer was 0,1 second faster.
Option 2 - Show timer as soon as we die
It's just silly that i can spend 20 seconds to wait for a teammates revive, give it up and spawn myself just to (sometimes) wait whole 18 seconds.
Option 3 - Let us decline revives from teammates
Sometimes it's just better to start from the base instead of the battlefield, give us the ability decline so our teammates won't waste time doing something you don't want to.