Adam Clarke on Acts 16:27

The keeper of the prison - would have killed himself - Every jailor was made responsible for his prisoner, under the same penalty to which the prisoner himself was exposed. The jailor, awaking, and finding the prison-doors open, taking it for granted that all the prisoners had made their escape, and that he must lose his life on the account, chose rather to die by his own hand than by that of others. For it was customary among the heathens, when they found death inevitable, to take away their own lives. This custom was applauded by their philosophers, and sanctioned by some of their greatest men.