###INSTRUCTION: Fix grammaticality of the sentence: When we arrived under the hotel we went straight to the beach and went swimming but suddenly my friend shouted, , Help me '' and then he disapeared only after a minute I've seen some blood plus the sea so I swam towards the lands but I recognized before something big is near me, then something touched me and I died from a heartatack!
###RESPONSE: 
When we arrived at the hotel we went straight to the beach and went swimming but suddenly my friend shouted " Help me '' and then he disappeared. Just a minute later I saw some blood in the sea so I swam to the land but I realized that something big was near me, then something touched me and I died from a heart attack!
When we arrived at the hotel, we went straight to the beach, and went swimming, but suddenly my friend shouted, "Help me, help me!" and then he disappeared. Then, he saw some blood on the beach, and he was stunned by it, and he swam toward the land, but I realized that there was something bigger than him, and I swam towards the lands, but I couldn't see anything in the water because of the sea, so I swam towards the lands, but I didn't know what kind of blood it was, and I didn't know where it was going.