Now, let's say the merging truck was gunning it so fast that the car couldn't pass it if accelerating. Then it isn't like the self driving car can magically pull a Go Go Gadget and stilt-wheel over it.

Never mind that a self driving car would have solved this before it ever came a problem, but let's hypothesize here:

If for some reason the trucks were non-self driving and the car was self driving and we hit this situation, a self driving car would be calm enough to swerve into the ditch seen at 3-4 seconds, and hard break if it felt it couldn't accelerate in time.

It would do some damage to the tires, but if it can't control the trucks this would be the safest option in a split second scenario. One that none but the most professional drivers would think of in a similar situation.