I made a video with several examples for both downstairs and upstairs.

When crawling prone and approaching the stairways to go down stairs, if you press a key to stand up to crouched position, the character will get launched and make a super jump.
Depending on the structure, you can glitch through the ceiling and land back. Sometimes , if there is a platform nearby, you can navigate and land on it. Happens almost always when trying to reproduce.

Also, when crawling upstairs and again getting up, the character would get to the top very quickly. I think the stairways speed is too quick, compared to regular jogging speed on floor.

While reproducing, the character's body would be very 'nervous', shaking while on the stairway. When landing, I would sometimes get the slow walk bug (crouched normal speed). It would cure when laying prone again and getting up.