Apostate prophet searches for his lucky number; how many times can one apostise?

In answer to the video "Top 5 Misconceptions About Islam - Debunked (Merciful Servant)"

Also, anyone can leave Islam and come back time and time again without punishement or being killed 4:137 which bellies the idea of killing a person as a punishement for leaving Islam or wavering in his faith. However God will only accept his repentence if it is sincere 3:86-89 and not followed by constant periods of disbelief then belief 4:137. 

As reported by ibn Abbas 

"A man from among the Ansar accepted Islam, then he apostatized and went back to Shirk. Then he regretted that, and sent word to his people (saying): 'Ask the Messenger of Allah [SAW], is there any repentance for me?' His people came to the Messenger of Allah [SAW] and said: 'So and so regrets (what he did), and he has told us to ask you if there is any repentance for him?' Then the Verses: 'How shall Allah guide a people who disbelieved after their Belief up to His saying: Verily, Allah is Oft-Forgiving, Most Merciful' was revealed. So he sent word to him, and he accepted Islam."

Nowhere does the Quran say a person must be punished or killed solely for the act of apostasy and all it mentions is that apostates shall face a terrible punishment in the Hereafter.

This of course excludes those who apostize unwillingly, who are

3:86-91,16:106"compelled while his heart is at rest on account of faith".

Such a person is compelled to renounce faith with his lips due to imminent danger on his life while he remains a firm believer in his heart. This is what is often referred to as taqiya. The Quran doesnt condone lying, rather commands to uphold one's pledges, to judge with equity, to speak justly, kindly, with integrity, without corruption, with the outward locution corresponding to the intent 

4:5-9,135,6:152,2:83,235,3:32,70"O you who believe! Reverence God and speak justly". 

It is further to be noted here, that although martyrdom in the cause of faith is highly meritorious, still the Quran absolves those who sincerely, not out of lack of faith, cannot go to such an extent because

2:233"no soul shall have imposed upon it a duty but to the extent of its capacity". 

Saving life takes precedence over following the law. That is why a Muslim may eat pork if facing starvation. Exactly what Jesus taught in the Gospels when he transgressed the sabbath by citing David's example.

Punishment in the hereafter for the sin of apostasy is therefore solely the lot of the one who willingly, without any compulsion renounces Faith and:

"opens (his) breast to disbelief-- on these is the wrath of Allah, and they shall have a grievous chastisement".