How do I get my lock to work?

Not exactly sure what "lock" is supposed to do, but check out how random() function works in Construct manual -> scirra.com/manual/126/system-expressions

random(a, b)

Generate a random float between a and b, including a but not including b.

You see, random() returns a float (decimal number), and you are trying to compare it with an integer (whole number). Try wrapping random() in an int() like this -> int(random(1,3)).

int(x)

Convert the float or text x to an integer (whole number).

Just as a general advice, create a text object for testing, and if unsure, set text to your random(1,3), just to check out the result.

Good luck!

use timers. Have when randomLock = 0 ,trigger once, start timer with duration random(1,3). Then have on timer complete set randomLock to 1.