Never trust anyone at your level at work. Many will step on you to get higher up. Just do the minimum when it comes to helping them. Let them fall on their own. I've been there many times where I helped others and they take all the credit, leaving me to look like I did nothing at work. Nowadays, I do nothing unless it's an order from the boss and if anyone wants a favor, I make sure to reply back via email and cc my boss so she knows what I'm doing and who I'm helping so they can't take all the credit for my hard work.