Dented to frame..safe?

Well, depents on which area on the toptube? In the head tube section, kind of dangerous, specially with that size! But in the centre, a couple inches near the head tube or seattube not really, I guess.

Take a look at the head tube, and dril the hole to the tt up, until you get the inner diameter of the toptube. And turnig yourself a short steel plug with nearly the same diameter of the tt.
Grease it with bearing grease or what ever.. and inseart it, should fall and stop until the dent starts out. And space it up with another plugs wood for example, till you see the last
one on head tube, on the vice with it, attention alloy frame!! And but a fat solid flat steel bar in it and hammer it with a buddy an the same time on the steel bar ends down. And the plug
should dent it back with the help of the grease. I would recommend to heat up the dent section so it's even easier and less stress for the material on that area. ( Not to much heat, take care about your lovely paintjob). :D :)

P.S:// The steel plug should have a medium size phase or round conical on the end!

What a lot of bollocks! - Should be okay, but don't drill your frame or try to knock it out, especially with an aluminium alloy frame.