From whence came that rocket?
Rocket-jumping didn’t originate in Quake, although it’s certainly where most of us first came across the idea. Now, of course it is most commonly used for getting upwards velocity in order to reach new heights. But sometimes at QdQ we sacrifice some excess health and armor just for the horizontal speed boost it can give.
Such rocket-running actually features as far back as the grand old days of DooM. There is a well in E3M6 that was designed to be reached by using the thrust obtained by firing a rocket into a nearby wall. (This LMP by Travis Almand shows the trick in action.) In fact, your objectives here could be fulfilled using either of two other strange bits of DooM also. Strafe-running will also give you the necessary speed increase, and the trigger inside could even be activated through the wall from the outside instead.
A question I raised in the original article was: if rocket-jumping took id by surprise after the release of Quake, what was with the Ring Of Shadows secret in E4M4 (The Palace Of Hate) that can only be teleported to using an explosive boost? Thanks to the people who wrote to suggest explanations. Of course, at that stage in the game, one does not have the rocket-launcher, just the grenade-launcher. And in fact, one does not even need to grenade-jump to reach the teleport. It is sufficient to drop a grenade into the provided hole and stand above it: the explosion will push you high enough to get up into the teleport with having to jump. So it would appear that whilst id knew that explosions could push you around in useful ways in Quake, they hadn’t got as far as thinking how this could be combined with jumping and with the ability that the rocket-launcher provides to make explosions underneath you just about any time you want them.