there are "Palestinians" who live in Israel. They are called Israeli Arabs (oh you didn't know that Israel wasn't a purely Jewish state?!). the fact that you assume the attack was carried out by a Palestinian entering Israel proves that you dont know how successful the Wall has been in stopping terror. the problem comes with Arabs within Israel who may still harbor hatred against the state, and the balance between maintaining the rights of arabs who have Israeli citizenship.
Turkey: 5 killed in clashes between authorities and PKK (Reuters)
from the article: War won't stop rocket fire from Gaza