Just wondering how much room I'll need. I want to buy one and leave it at the gym, but there is only ~10m of space I can safely use. I assume and I can just run to the other side and push it back right?

Does the design matter? I'm looking at something that's rectangular that is about 115 US$, but I normally see people using a triangular one.

Will it tear up the floor of the gym? It uses whatever that artificial wood is called. Any issues with concrete?

Before I decide... buying a prowler would be my best bet for HIIT, right? Gyms don't have anything other than spin bikes, there arent any steep hills, but my building has 25 floors if stair sprints are useful.