Usage of only in this scenario

I have trouble understanding the usage of "only" in this scenario.

I was watching the Walking Dead, and I came across this scene.

"How many blood transfusions did you get?"

"2, only 2.

Is "only" used to say that the speaker thinks that "2" is very little? I'm unsure because they gave off the impression that '2' in such a short time is a lot. Though, I've also thought that "only" is used to imply that you think something as very minor (very little). Am I wrong?

This is indeed "only" in the meaning

as a single fact or instance and nothing more or different

This is because that number of transfusions can be both a little and a lot in two different senses.

In the ordinary course of life, getting any transfusion is extraordinary, and therefore even one is a lot.

However, after you have been injured, under circumstances where people would expect it to be grave, emphasizing that you needed only two says that while the injuries were serious, they were not extremely serious.