Thoughts on this play?

This was a tourney that I played in last night. Blinds were 300/600.

I was in middle position. One guy in early position limps in, next guy to act raises the pot to about 2500 with Ah7h w an effective stack of about 30k. So its my turn to act and I hold Kc10c. The original raiser has been very aggressive at the table and I noticed that he played a lot of funky cards (mostly suited). Picking up on this, I 3bet to 7500 (I'm left with a little more than 20k) and everyone folds but he makes the call. Flop is 10, 5, 4 rainbow. He, who was first to act, donk bet me all in. After about a minute of agony, I reluctantly made the call. 6 is turn and 2 is the river.

Any criticisms of this? My original intention was to have him lay down the Ah 7h but I'm thinking, perhaps, I should have just pushed all-in instead of 3bet?

Also, is that donk bet usually a sign of weakness? I presumed it was.

Alot depends on the stack sizes behind you. If your all deepstacked I would 3B to around 6K vs this villian based on your read. Shoving pre is bad with your stack size (45BBs) with people still left to act. Someone could wake up with a monster behind you and get all your chips because you were not thinking it all through. You need to leave leave yourself room to fold to a 4B shove and still have 35BBs. Remember your play was meant to steal his chips not spew all yours.

my fear is to not thinking it all through,maybe not a fear ,but a weakness in my game late in a tournment.

i think your raise may have been a little bit big, but as for going all in this position, it is a little risky as you have several players behind you. If i was in late position i may of been tempted to go all in to push the maniac off his hand.