Even with all 3 laws being intact and unaltered, said robot can potentially be extremely dangerous. The conflicts generated by the three laws interacting with the real world could lead to suicidal depression, homicidal insanity, finding religion, or any number of other results.
If you want to see a fun re-mangling of the 3 Laws, look at the robots in the (tt-RPG) game '
Paranoia'... Once they figured-out they were the property of Friend Computer, they could basically do what they liked...
...
Trouble Shooting Troubleshooter (Omake)
"Excuse me? What are you doing in the Out-patients Ward, Brockton General, this time of night? I'm Panacea, by the way."
"I think... I just came through an experimental World Gate. We were just checking out... a lab where there'd been strange disappearances. I figure I just found out why."
"You seem to be bleeding, a little, can I help you?"
"Are you a medic, too? Sure."
"You... do realise that you've an amazingly accurate flesh body over a non-living endoskeleton? That should fix that injury, and a few of those nasty bruises you had. And, those old burns."
"Thanks! I feel a lot better. I know I'm wearing a red jumpsuit, but the blood does make a mess after a while. Thanks for fixing the old laser burns. My skeleton is laser-resistant, of course."
"Have you... always been like this?"
"No. I was originally a surgical-practice droid, laser-resistant skeleton because the trainees aren't always as careful as they should be, with their laser scalpels. But, I was drafted. They always need more Troubleshooters.
This place looks... rather lower-tech than what I'm familiar with. Is that... Outdoors, out that window? I've never been Outdoors..."
"You... said you were a medic? Are all... droids medics?"
"No. They downloaded full medical skills in me, so I could support my Troubleshooter squad. I've not had need... to use my laser scalpel. Yet..."
"Right. Are you... hungry, or anything? It looked a long time since you last ate."
"Yes. Some food would be good. I've heard of these things called 'hamburgers'. Any chance of getting one of those?"
"The hospital food... isn't ideal, but it is hot and filling. Yes, I think they're serving hamburgers. I could use some food, myself."
"Excellent! Just one thing... This world isn't run by... an All Powerful... Artificial Intelligence, is it?"
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AN: Would a recycled 'surgical practice droid', in a red Troubleshooter jumpsuit, armed with a red laser pistol, and... advanced medical skills, count as a teenager? How would they fit in Brockton Bay?