SilentDemon555:
What I need to know how to do is how to move servos while a for loop is running. It can't interrupt the movement, but it should have the ability to interrupt movement if I need it to.
You need to have some algorithm for determining the required position and speed of each servo. That might be a hard-coded timed sequence of actions if the biped is inherently stable when walking, or it might be via a feedback loop monitoring its state of balance.
For timed movements, you have a piece of code that runs repeatedly for each servo which calculates the required position for that servo at that time, and if it is not the same as the current position it moves the servo to the required position. You simply call this repeatedly for all servos fast enough to produce movements as smooth as you require.
I imagine that the code to calculate the required position and speed will also be controlled by some code that controls the gait i.e. decides when the left leg needs to swing forward, when it needs to stop, when it needs to straighten the leg to contact the ground, and so on. This gait management code would also run repeatedly and determine where the biped was in the walking cycle and whether it was necessary to advance to the next part of the walking cycle. (This is also where I'd expect to see weight transfer initiated.)