Clearly Ike is pretty pee'd off as he has been harassed since the night before and threatened for no apparent reason as he was not the instigator of the animosity. Try putting yourself in his shoes for a moment or two and see how you would feel.

Feeling unsafe and unsure, he armed himself and went on about his business accompanied, according to testimony, by a fellow named Stilwell, but we don't know which one as there are about three Stilwell's in this story.

From a Law perspective, we know Ike should have not gotten a gun, but from the angle of human nature, one should understand his uneasiness. After all, the threats came from men who were supposed to uphold the Law, didn't they?

The arrest by Virgil and Morgan didn't help though it was justified; but the continuing and unnecessary harassment in the courtroom after (according to the clerk in attendance) was pouring gasoline on hot coals. Ike felt even more threatened, sure that if the Earps could find a legitimate way to trigger him into appearing to defend himself, they would do him in.

It appears Ike may also have suffered a concussion from Virgil's attack as he sat quietly holding his bleeding head in the courtroom until provoked further by Wyatt and Morgan. Safe to say, he was miserable and operating on a short fuse...therefore he went to see about a weapon from his friendly neighborhood gun dealer. One can understand it though we all recognize it as a foolish move under the circumstances around him.

He was fortunate Frank and Billy found him when they did.