Then maybe it's because he's still [i]human[/i] too?! And to err is his nature. :P
There's also this reason that it would be really hard for him to control Ted's power, especially in the face-off at Kirby Plaza because he was also absorbing other people's powers (super strength, technopathy, clairvoyance, phasing) ALL at the same time. So yeah, maybe the explosion was really inevitable at that moment.