I dissagee.
I firmly believe that Doom is NOT above such things; while he is not a serial killer, he will gladly and casually murder scores of people as long as it's necessary for his master plan. He's really an "ends justify the means" guy.
And if I remember correctly, the agreement WAS on his terms; my understanding was that Doom considered this contract as nothing more than a mutually beneficial alliance, not an agreement of servitude.