Impact to loosen head bolts?

[cscmc1]

OK, the 602 has me confounded. I have broken TWO of the 10mm triple squares off in the head bolts on the 300d. The last one ripped my hand open good when it let loose. I got 4 of the bolts loose with LOTS of torque, but this 5th one is really irking me.

Any reason I can't try the impact on it (whenever Napa and/or Autozone can get me replacement tools)? Apparently King Kong must have torqued these when last they were done. I really don't see how else I am going to get it out; the torque was being evenly applied with a decent sized breaker bar. Stealership is too far away to make a run for the $30 Mercedes wundertool...

Oh, and I have the tip of the last tool stuck down in one of the recessed bolts (under the cam bridge). That'll be fun to get out!

What a PITA...

Thanks for letting me vent!