At case D, your probability changes from 99% to 50%, because only people who survive are ever in the situation of knowing about the situation; in other words there is a 50% chance that only red doored people know, and a 50% chance that only blue doored people know.
After that, the probability remains at 50% all the way through.
The fact that no one has mentioned this in 44 comments is a sign of an incredibly strong wishful thinking, simply “wanting” the Doomsday argument to be incorrect.
The problem is that using a bounded utility function to prevent this sort of thing will lead to setting arbitrary bounds to how small you want the probability of continuing to live to go, or arbitrary bounds on how long you want to live, just like the arbitrary bounds that people tried to set up in the Dust Specks and Torture case.
On the other hand, an unbounded utility function, as I have said many times previously, leads to accepting a 1/(3^^^3) probability of some good result, as long as it is good enough, and so it results in accepting the Mugging and the Wager and so on.