Will the slide lock levers move all the way down to the bottom of the slots in the frame? If they will, then here are a couple of things to try.
First idea:
Turn the gun upside down and cycle the slide vigorously several times. It's possible there's a bit of broken plastic from the cap that you may be able to dislodge. After you've cycled the slide upside down, leave the gun upside down and see if it will field strip that way.
Second idea:
Lock the slide back, and rotate the lasermax guide rod a little bit, drop the slide and try the field strip again.
There may be something that's attached to the guide rod thta is hanging up in the small slot(s) in the frame forward of the slide lock spring. It's not a large area for something to hang up, so the odds are reasonably good that you may be able to turn the guide rod so that whatever is hanging up is positioned so that it won't catch on the slot(s).
Third idea:
Try a combination of the above where you vigorously cycle the slide with the gun upside down and then, with the gun upside down and the slide locked back, try spinning the guide rod to see if you can clear the obstruction.
If none of that works then I guess it's time for the brute force approach.
Make ABSOLUTELY sure that the trigger is in the fully rearward position and the slide lock levers are all the way down and held down firmly and then apply significant force to the back of the slide to force it forward off the frame. There's not much to damage in the part of the gun where the bind is occuring, and the surface area of the bind between the guiderod and the gun has to be very small because that part of the frame doesn't have any large areas where something can hang up.
I think that there's not much chance of doing any significant harm to the gun, although you may end up with some scratches inside the frame.