[weegee]

Being killed by the infidels would have made him a martyr under the rules of Islam.

There aren't "rules" under Islam. There are laws. It is a political-legal system shielded from criticism by religious overtones.

If being killed by infidel is so noble and they are slaves to peace, they would lay down their weapons and accept their deaths. They serve Islam in taking territory for Islam. The kufur are captured as slaves or killed as blaphemeres. It makes no difference in the end to them as we are sub-humans (e.g. Jews "are" the offspring of apes and pigs).

[SauronOfMordor]

If being killed by infidel is so noble and they are slaves to peace, they would lay down their weapons and accept their deaths.

A muslim could reasonably consider that being killed by infidels as a direct result of actions he took to kill infidels, qualifies as the same as being killed in battle and thus merits martyrdom status