He wasn't suicidal! If he was he would of just let himself become one of them, but he didn't. It was pretty much gonna be a one way trip because like Omid said something about a maw of darkness, with a possibility of zombies in there. Well, I was sure Christa was going to die, but of course Kenny tried to save her, I think the word is sacrificing his life for others, if you had Christa instead of Ben, then I think that he was thinking of clementine and who was going to look after her when lee turned, because they all knew that there was no chance of survival for Lee.
So, no I don't think that Kenny was suicidal, if you want to reply saying I'm being dumb and there is no arguement to be found blah blah blah then please do it will be interesting to find out what others thought