I think you sometimes let your bias obscure your memory. Cristina encouraged Owen to tell his Mom he was home from a war zone after he was avoiding his Mom. Cristina was supportive and even accompanied him on the trip.
I respect your opinion but I don’t think these situations can compare. The “trip” you mentioned was the 5 mile drive to Evelyn’s place? I don’t see how that demanded a lot of effort from Cristina, or even got her out of her comfort zone. I wouldn’t be surprised if she was thinking the whole time about how much she was missing an important surgery to be there. (haha okay this was mean but true).
The day Amelia proposes to sell her husband in order to get surgery favors we can come back and discuss this topic, because at this point, we are comparing water and wine.
Here is a quote to cheer you up: