/ "Hanged Jesus portrait" - Common app - Evaluate a significant experience
Even if you had not stated that you are an international student, I would have been able to tell- there are certain phrases in your writing that sound stilted or unnatural, indicating that you're not familiar with English as a native language, even though in terms of structure your essay is well done. Here are a few comments:
Consider capitalizing "catholic" in your first sentence.
"All of volunteers are gathering at here, Padre's room at the hospital."
A missing article, perhaps: "All of the volunteers [...]"?
"Before we serve to people, we pray to God, and minute silence, and then we separate each other to start serving patients."
The phrased "serve to" seems awkward to me; I don't think the "to" is necessary. Also, what are you serving- food? Or do you mean "serve" as in performing service, in a more general way? "And minute silence" should probably be "take a minute of silence."
"After pray, Sr. Shin says"
"Sr."? Do you mean "Dr."? Or is this meant to be an abbreviation of "senior"? Also, "after pray" should be "after praying".
"I nodded what she said and left the Padre's room door. Before I enter the Intensive care unit, I think billion situations."
Change this to "I nod in response, and leave Padre's room. Before I enter the Intensive Care Unit, I think of a billion possible situations."
Remember, keep your verb tenses consistent- if you start in present tense, remain in present tense.
"As I entered Intensive Care Unit, I knocked down about thirty seconds. People are moving busily to serve patients effectively. When I knocked down myself, Mrs. Kim, who is my co-volunteer, explains what my job is, how should I do, and inform restricted behavior in this unit."
First of all, I don't know what the phrase "knocked down" means. And how do you knock yourself down? Do you mean that you fell down? Or that you were knocked down by someone else? Once again, you've switched to past tense, as opposed to the present tense of your first paragraph. Also, change "inform restricted behavior" to "and informed me of the restricted behavior in the unit."
I think you have a good start to this essay- most of the changes I would make are grammatical errors. Read your essay to yourself out loud and see if you can catch all of the mistakes. You do a good job of describing the experience, but it could be even better if you could bring in some of your plans for the future.