Crash the server
Impossible you are not admin and are stuck in a cell!
Attempt to guess the admin password, if succesful, ban the guard and destructo-wand the bars.
Blockhead would attempt to do so but he has not learned about the escape menu yet! at this point he shuts down blockland by closing the launcher.
what the stuff is with all of the blockland adventures
I was making one in the timeframe Lego Lad posted his, I was then to lazy to bother being lazy and not posting it!
go clicking around I guess. jails usually have hidden items in cells when you click stuff.

Lets see what we have to work with, a cell door, something relating to an air vent, and a life time supply of popcorn. But it will not last a life time since there is only so much you can eat before it expires! Them bastards, just another example of police brutality. Giving this poor blockhead popcorn that he can never hope to finish wasting a perfectly good supply!

Hmmm now lets see about this air vent.

Well it is awfully close to the popcorn supply, blockhead becomes deeply cautious. Something bad could happen to the popcorn! Or even worse Blockhead70160!
He attempts to open it by giving it a few good clicks with your mouse! annnnd. . .
Nothing, huh oh well. So that's not an air vent??? Now what? How about that cell door?
Blockhead wonders if. . .
He could just sort of. . .

Click it! His eyebrows raise suggestively out of an area where he previously had none! There seems to be no events keeping Blockhead in there. Sort of like no one thought he would try opening it. Sort of like, they expected him to go along with it and stay in his cell.
Blockhead70160 steps out of his cell and into freedom! But what about. . .
The officer. . .
Objective: Find away to get away from the guard!
I recognize I am doing to much plot development on my own part. yeah I will attempt to do that less and make the forums come up with most his actions.