可就:could be... it highlights the emotion.
就义:for example, a country invades your country and u fight with them. then u die. now we can say: 你就义了。
就义 comes from old chinese. 就 means trend, it is a verb. 义 means all kinds of positive, grand emotion. for example, u die for your country, or u sacrify for your friend etc. all of these can be called 义. so 就义 means u sacrify everything (even your life) for some kind of 义.
today, 就义 means u die for your invaded country.
in your example, this is obviously a kind of joke. for example, u broke your TV and ur mom was very very angry. so u left your home and was staying with your friend for a while. then u said: I want to go home. ur friend said: 我跟你说 你现在要是回去了你基本上可就就义了啊。---- i am telling you, if u return home now u will be a dead man (because ur mom gonna kill you).