After 2years relationship my boyfriend hit me for the first time

That's a tough one. Normally I'd say get out and don't look back because the next time he could kill you. But if he really is claustrophobic he could have been having a major panic attack and may not even have been able to control his actions. You know him best. If you believe it was a one time thing then give him another chance, but only if he agrees to get counseling for his claustrophobia and possible violent tendencies. Agreeing to this will show his sincerity and committment to you, and if he loves you it is the least he can do. And at least one of those sessions should be the both of you talking to the counselor as a couple.

Claustrophobic or not, there is NO reason to hit a woman.  If he does it once, he'll do it again.  Get out of the relationship before it's too late.

This will probably surprise the people here who know me, but I think you should give him another chance. Normally, if a man hit a woman, I'd be right in there saying boot his ass out. But these were not normal circumstances. He may have tried to hide and control it, but he was literally scared to death. Claustrophobia is bad enough. But even people who don't have claustrophobia will freak out completely and lose control of themselves if an elevator gets stuck. Hell, even I would freak out a bit and I'm one of the calmest coolest people there are. Your boyfriend panicked and he wasn't thinking clearly. It doesn't help that he can't speak the language. If he ever strikes you again, then boot his ass out. But this one time was very much an extraordinary circumstance, and I think it's worth forgiveness.

To make a long story short: 
1.  I believe that he hit you only because he was under
     a panic attack. 
2.  That is not a normal condition. 
3.  But that does not give him any justification to hit you. 
4.  So:  Give him another chance provided that he'll
     learn to control his anger (attend a special class).
5.  ..... and if it happens (or any other sort of anger attack)
     again, dump him immediately !. 

I have to agree that this guy should be given another chance.  He was not himself during his panic stage, and chances are he will never hit you in any angry way again...however....you may need to demand that he get help for his emotional state, because if you stay together there could be many other situations like this one, and you don't need a partner who will go to pieces when the times get difficult.

I agree that he may have been in a panic and over reacted.  That said, there is no excuse for his behavior.  The two of you need to have an in depth conversation about this and you need to let him know that it's unacceptable under any circumstances.  Tell him that if it ever happens again, the two of you are finished...no ifs, ands, or buts.  Also, as has already been suggested, he needs to address this with someone who can help him to address his fears and control his reactions.

It wouldn't matter if he was going into cardiac arrest, or a seizure. A gentleman doesn't hit. Bottom line. A real gentleman has self control, and never allows his anger to go unchecked. People become terrified, and irrational, but they don't become violent, when in that mind frame, unless there is another underlying issue. 

I don't know what to tell you, other than...that wasn't normal behavior.

You needed the pss slapped out of you or he wouldn't have done it. I needed the piss slapped outa me, to late now, I reap what I sowed.