Side looking minimally invasive surgery instrument assembly

A surgical instrument assembly comprising:

• a guide tube comprising a proximal end, a distal end, and an intermediate position between the proximal and distal ends;
• and
• a surgical instrument, wherein the surgical instrument is configured to pass through the guide tube, and wherein the surgical instrument is configured to exit the guide tube at the intermediate position;
• wherein:
• the surgical instrument comprises a parallel motion mechanism, the entire parallel motion mechanism of the surgical instrument being distal to the intermediate position in a first configuration;
• and
• the parallel motion mechanism of the surgical instrument is configured to heave and sway a distal end of the parallel motion mechanism while preventing changing of a pitch or a yaw of the distal end of the parallel motion mechanism relative to a proximal end of the parallel motion mechanism.