When spoken to, Burke has an unusually deep voice as well as wearing trenchcoat attire, with a pair of dark circular glasses.
If you have not already defused the bomb for this quest, Burke will offer a preposition for you to rig the bomb and to meet him at Tenpenny Tower, a location in Fallout 3. If you do choose to rig the bomb and go to Tenpenny Tower, there will be a suitcase with a mechanism rigged to blow up the town you rigged them bomb for. (Megaton) If you choose to blow up the town, you will witness a devastating explosion from the Tower, and Mr. Burke will grow with excitement knowing you killed nearly over 100 people. From there, he will give you a key that let's you access a loft in Tenpenny tower.
HOWEVER, if you do not choose to do the stated action above, and defuse the bomb, Mr. Burke will act hostile towards you and tell you, "We have no business together."
In other events, if you decide to kill Burke, you will recieve good karma, and you will be able to collect his equipment.
Fallout 3 Player's Friend: Blow that shit up!