During the beginning of the 2014 version of Robocop Alex Murphy is severly injured by a car bomb when he is forced to check his car at home after the car's alarm system activates at night. But this car bomb was actually planted much earlier when he was visiting his injured partner at the hospital during the day. This is even emphasized when the two corrupt cops tell Vallon that Murphy will be at the hospital during the day, providing an easy chance for getting him out of their way.
So why didn't it detonate earlier, seeing that the bomb was to some degree smart enough to detonate when he was near and to drag him to the car in the first place (no matter if due to a smart arming system or a remote-controlling bad guy). I cannot see either an in-universe reason in the story why the bomb didn't detonate (or was detonated) earlier, like at the hospital or on the streets, nor a story-telling based reason why it had to happen at home at night (apart from the fact maybe that if he had been inside the car while driving it could have been more effctive, completely killing Murphy).
So is there any explanation I have overlooked in the story or any other reason why the bomb detonated at home while planted much earlier at the hospital?