The way you're raging right now is exactly why you shouldn't focus on getting a KEM Strike. There are too many factors that go into getting one such as connection, spawns, the enemy team's skill, luck, etc. The best advice I could give you is to not attempt to get that killstreak. If you happen to get a killstreak that far, then go for it. Don't make it your priority though as it only causes more problems.
I would rather run Assault or Support if I'm even trying to get something like that. You would at least have something to show for that streak if you are killed as supposed to having nothing from Specialist. In that way, you have streaks left over that'll help your team more as opposed to not having anything to support yourself.