I'm using tails with mac address spoofed, but in order to connect to my college's wifi I have to open up the unsafe web browser and log into the wifi using my username and password, which are known by the college administration to belong to me.
Am I safe as long as I use tor browser after this, for all dnm related activity, or is this a security risk?
Not great for your OPSEC. A competent sys admin could track that you were on Tor, and if so inclined, check where the links went. I would make any orders from the nearest Starbucks.