I've had this suspicious recently, that walking diagonally (holding down forward and A/D at the same time) could be causing the player to move slower. It might just straight up be confirmation bias, but as soon as I focused on only using mouse to affect the direction I was moving, my times started to consistently get faster. I don't know how to properly test this, but I'm pretty certain it could save somewhere around one second.

Yeah I did have these feeling when walking around tight corners like the starts after elevator and the tiger's room. It wasen't too noticable for me to put much thought into it, but it was odd that some good runs were slighly slower and some bad runs were slighly better if I randomly choose to turn with my mouse or A/D; the problem is that I do not know which one of the two caused the player to move slower.