I'd like to present my own (and totally subjective) point of view.
There are IMO two things to note.
1, I think that making those events optional in the menu would solve this problem once for all (and wouldn't be hard to make too) so for the sake of visually or motorically impaired gamers it would serve the purpose.
2, I disagree that it's senseless. Tension can be quite nice to have in the game providing you don't have to backtrack (as IMO you don't need to in CoM). I always find strange for example in The Longest Journey the infamous scene with The Gribbler.
You're attacked by a vicious creature which is obviously going to eat you and so the "run-around-the-table" begins. You watch it for a while, then go, make yourself a coffee, come back the gribbler still runs around with April (she's in quite good shape if you ask me to run for such a long time). Then someone calls you, you speak for 40 minutes on phone, then get to the screen and they still run around.
So the tension is automatically gone.
So the timed sequence (if done right) would present the tension and feeling of urgency which (in case of this Iris' return) is really there. (it could have been done by not using real time per se, but for example action counter like it was done in different games, but the principle of punishment should be there).
Another interesting shift I've noticed in the adventure game development is that if you play any game (chess, football, hide and seek) someone wins while someone else loses. Here the game can never win over you, because we don't allow it to win (even if it would have been fair and logical in the context). So in my opinion adventure games turned away from "games" to pure "interactive novels". I myself confess that it's very convenient that I can't lose and it perfectly fits the mood of Myst for example, but in the case of a detective novel, where you really go to dangerous places, I still think it had its point to bring actually at least some danger in.
In closing I don't (and will never) argue with people who are impaired, they should have this option present in "accessibility" tab
for sure. But if you take the danger out of the developer's hand entirely, all games will turn into "relaxing" experience which in my opinion (at least in case of this last scene) wasn't.
Just my 2 cents.